The respawn on this octupus type monster is unclear. It's been documented to have anything between 8 and 24 hours respawn time. It drops the Joyeuse, and level 70 rare/ex sword. When we killed it, we had more than 12 people, one pld and one nin (all 70++). Even with two white mages and two red, we managed to get 4 people killed, so be prepared for an exciting fight.
Chary's special attack "Cross Attack" can do loads of damage (more than 800+), so be prepared for some quick curing or raising.

Another thing to note, his spawn area is located in one of the treasure basements beyond the gold beastcoin door, so make sure you have a few handy to get all of your alliance to the point.