The Year of Blood

The Year of Blood began in the spring of 221 AA. It did not begin like any war in history. The Grel decided they were bored with life in Nesh Tel' All and it was time to set out on a great hunt. The alchemists tried to stop them but were quickly overpowered. Then, as they tried to leave the city, the guards tried to stop them. The Grel interpreted this as a legitimate hostile action and lashed out violently. They laid siege to the capitol from within for two days and three nights. The city was in ruins before they decided to move on. The Grel discovered fighting humanoids on this scale was quite a challenge and decided to see if how they compared to other countries.
The next two years almost saw the end of the civilized world. The Grel attacked and raided cities and towns indiscriminately. Attacking anywhere that had a sizable fighting force. They would cripple the military force and then move on. This would leave the cities and towns vulnerable to monster attacks. Towards the end of the Year of Blood The Grel would start leaving hunting parties behind to protect towns from monsters while they refortified. This behavior baffled everyone.
Then it just ended just as quickly as it began with The Midday Night.