Some notes on Jaeil:
For TLP's (and specifically for Kunark/Velious in era Hole V1.0 zone)
Jaeil spawns in the DZ version of the hole. His spot is actually considerably closer to the DZ entry point than to the normal zone in. You will need to kill various tunnel roamers/patrols but there are very few spots that require handling more than 3 mobs.
Jaeil himself will be just after a three golem area when coming from the DZ entry. You will want to additionally kill a roamer that will be coming down the tunnel from the opposite direction (so that he doesn't add).
On turn in, Jaeil the Insane spawns. He has 20k HP and a min hit of 38 and a max hit of 162 (DB/DI 38:6). His DPS is about 27.
To solo him, engage (away from the water!). Snare. Melee him down w/ CoF casts in between swing blocks. You'll probably need to back away and heal about halfway through. He does summon, so back off wait for the summon and then cast your heals. Alternatively use a healing pot.
It was harder to get to him than to solo him.