Goblin races

Physiology

Goblins are a small race that vary wildly. There are a few similarities, though even these are loose at best. Goblins typically stand no higher than 4', though rumors exist that there are some truly monstrously large Goblins. While these rumors remain mostly unsubstantiated, the rumors source cannot be ignored. They also typically have a skin color that matches their hair color. Interestingly, their skin color seems dependent on the climate and overall temperature of the region they live in. Warmer the climate, the greener the skin. Colder, they turn a pale purple color. The men and women look largely similar, though the women do have wider hips, and recognizable chests. Though, men would still say they look like children with big floppy ears, and thus most Elves and Humans find them unappealing.

The Difference between the northern Clans and the Southern Clans seems to be superficial. They all seem to be about the same level of intelligence. Though if you ask me, strictly speaking, I don't think most give them their due in this regard. I think they are far more clever than we give'm credit for. Seen too many men die to sophisticated tactics and ambushes. But, back to your original question, the different Clans are very different looking, but act similar... -Royal hunter in the employ of the Baron, moments before dealing with an ambush of Goblins in the outer fields.

Culture

Their culture is a source of contempt for most cities near goblin settlements. They mostly consist of raiding, and most of their hierarchy revolves around who is the best at raiding, and bringing back more to help the clans. In terms of interculturally, their culture is very much about helping each other, and lifting up the weaker members of their clan. They are also very sympathetic to other Goblins and those that look like them. They are however, not particularly hostile toward anyone race outside their own, they just see all other races as sources of loot, and therefore subject to attack. Their culture demands that they raid for their livelihood, not out of a real desire. There are a few notable outliers in this line of thought, however.

Their greatest outlier is the Leader of the SkullBrood Clan. Ilgor is a very intelligent member of their society. She has made it her personal goal to reach out and contact the other Clans, and bring them out of their ways that cause them so much suffering.

"Why sire, she was so eloquent. Polite, and might I say Intellectual. I never would have guessed a Goblin to be so... Courtly."

"You have much to learn, learn to make judgement off experience. Yes she is a surprise, a welcome one at that, but we have yet to see what she will do with her Clan. I have every intention of making use of her Clan to aid in the the city and I should very well think that she has her peoples best interest at heart. There is no reason to judge her based on the fact that she is a Goblin. She was a far better diplomat than most courtiers in these days." -Conversation Overheard in the Court of the Baron, between the Baron and a member of the Wayfarers Guild.

The goblins are a hit and run race in terms of combat

Clans

The SkullBrood Clan

is located in the south bluffs of Glaion and is Home to the key figure Ilgor the High Priestess. This clan has recently under gone a massive cultural shift under her leadership.

The Clan has kept it's culture of helping each other, and the general affection found within the Clan. The Clan in it's old form would center themselves around their High Priestess and Chief, as they would be the acting Mother and Father of the Clan. A defacto point of authority, all decisions made by raiding parties must first be taken to the Chief and the reasoning explained. All loot would then be gifted from the Chief. The High Priestess would be the point of center for any confusion, emotional, or logical. She plays the role of the guide, and blesses the Clan members before raids and all raid offerings. She also will refuse to teach the words of Bhal to everyone except the next in line, and the Father. The Chief and the High Priestess are symbolically married to each other. Though this is not a true marriage, they do not sire children together, nor are they lovers of any kind. The Clan sees this as more of a balancing of power, as Bhal wants a unified leadership, though this doesn't seem to fit his general teachings. This has been a hotly debated topic as to why their culture does this, they do not seem to know either. Currently the Clan has one leader, and is a mix of both roles.

In times past, the Clan also follows under a few more cultural additions.

The Clan is also one of the most militant. They follow a hierarchy that follows, 

• The High Priestess & Chief
• The Raid Leaders
• Raid crews
• The rest of the Village

The clan revolves around orders handed down from the top, and the interpretation of it by the Raid Leaders. Though all those interpretations are reviewed by the Chief after the fact. The lower on the Hierarchy the less freedom in the clan. Most of the village is actually not allowed to leave the village unless given direct orders from the Chief or High Priestess. It follows a loose structure of squadron of soldiers, with Juniors commanders and Commanders. 

The members of the clan are also skilled hunters and trackers. The clan typically likes to stay out of sight until they attack. They use their small size to their advantage in each confrontation, being able to duck under swings most wouldn't be able to avoid. This has lent them the ability to be able to blend in better, and strike consistently.

"Though traditionally they have acted as many goblin clans have and that is of raiders and warmongers. This clan seems to be an outlier in the grand scheme of things, and probably have no significant impact on much."

Conversation overheard in the Library of the Baron of Glaion.

The Neckbreaker Clan

is located in the Ilse of Mhuzelt, not much is known about their culture beyond that they are goblins. Their Clan is a based out of the North Western area of the greater kingdom. This Clan is of particular interest in the Gnomes, not because they see them as dangerous, or profitable, but because the Gnomes want to know why they are pale purple.

"Why make such a fuss? Oh if you'll stop pestering me, Ill tell you that they seem to be able to craft more intricate tools than most other goblins. Hmm, I suppose that may be because of their proximity to the gnomish settlements on the Ilse. YOU don't really think they are smart enough to learn from others do you? I mean they are intelligent, but no more than a toddler or a clever dog." - Royal Vizier of Zybtine's court

The Tribe Of Hate

is a Goblin race shrouded in mystery. They live on a sizable island off the Western coast of the greater kingdom, just south of Mhuzelt. They are a much larger variant of Goblins and are much stronger. It is theorized that they also the most religious of the Clans, though it is unknown whether they follow the Cult of Bhal like the other Clans do, it is suspected that they do not. They are depicted as large, burly and a mix between green and blue.

The Tribe is the only known goblin race that are experienced shipwrights and sailors. Though, their massive size leads to their ships being colossal. It is unknown how many of them are out there. Many legends exist of fog enclosed ships that sail through the northern coasts however. Song sometimes being involved, sometimes not, it is seems that every settlement along the coast lines has a form of myth involving this type of ship.

The Tribe is a richly bardic one. They often start singing while working or raiding, the songs are usually of a somber tone and subject matter. Though while this music resembles sea shanties and bold jaunts and jigs, it wouldn't quite describe what they are doing, as they seem to sing compulsively and randomly. New songs in their ensemble are readily accepted and adapted to their cultural nomenclature.

The Tribe boasts a few unique abilities including temporal effects and a kind of storm calling. These manifest in their song, as while they sing, time appears to move slowly. Though this seems to be more of a charming effect rather than a hostile one. Among their Tribe where the song is strongest in it's members, a weak storm calling can happen. This is usually a summoning of mist or fog, very rarely they will summon rain.

"You were not what I was expecting, I thought I was meeting with the Goblins of my Clan, not the fabled Trolls."

"You met, you saw, now you believe. We agreed to see to your request, and we are prepared to accept, so long as you help us with our problems as well as yours" -Over heard Conversation between Ilgor and the Clan chief of the island.

The Clan of Wide Eyes

is a Goblin race that resembles Kobolds, only their eyes are very wide and have an intuition with Farsight. They are a Slight build, and long armed. They are also pale green, compared to the Skullbrood Clan of vibrant green. On the tips of their tails is also a tuft of hair, in seemingly random colors. This does not seem to fit with the skin color matches hair color physiology in normal conditions. Though their hair on their head does follow this general rule.

"There is a swallow, a delicate bird. There is a man yelling at this bird. They seem to be at odds. The scene shifts, and the man is dead in a burned field. The swallow soars high above, looking mournfully at the field. An arrow, a gold coin, and prince of the land sit in thrones of the Great Lake. The vision fades, I cannot see anymore...I am tired...Hungry" -High Priestess of the Clan of Wide Eyes giving a reading to a knight who had come to see his fortune told.

Racial Abilities: All Clans of Goblins share a few common abilities that vary in strength from Clan to Clan.
Charm: This is a weak speech effect that forces the listener to focus more on their words. While this doesn't force the listener to do anything they do not want to, or put the listener under compulsion, It does make them easily heard when they want to be. This is an effect they can control. This effect does not apply to any other goblins however. Adds a static +1 to all speech based rolls
Curiosity: This is an ability for the race to learn skills slightly more quickly than other races. The SkullBrood and Wide Eyes Clan have an enhanced ability for this. Adds an additional level to a single Knowledge based skill upon leveling up

Racial Challenges: Historically, all goblin races are not well tolerated outside of their strongholds and villages. Thus, they have to deal with the issues of being second or third class citizens in the holds they reside in. Through centuries and ages past, this seems to be the case, and it has just been ingrained as fact of life.  -2 on charisma based rolls. 
Thematically however, players should realize that this is mostly based off the fact that the goblin cultures of the world have this reputation because of their faith to Bhal and the practices he demands from his people. There are outliers in all though.