Yesterday we had a DnD4e session to kill the final boss of a, now in total, 4 session dungeon. This fight took us 7 hours (irl).
- The boss had an AoE ability that would shoot a fireball for 1d100 with everything below 50 adding half of the dice roll to the dice roll. This was a standard action and took a minor action to spool up. It was used about every other round.
- Next to that the boss had 1800hp.
- If you would stand in front of the boss it would also bite you and practically one-shot you for 60-90 damage.
- It also used a type of gravity magic to pull us together to hit his AoE on more of us.
The mechanics of the boss seemed very legitimate to me and they didn't seem too overpowered however, i think that the amount of hp was a bit overdone. The reason i'm asking is that this is the first DnD story we have ever played (including the DM) so none of us has anything to compare it with.
Setting: DnD4E, All around lvl 12-13, Well balanced party (support, tank, Healer, melee DPS, ranged DPS, Tanky DPS), Our DM customly makes all creatures in the campaign
EDIT:
Additional info: We started the fight after an extended rest. Just before the bloodied value of the boss we we're trough most of the standard/minor action encounter and daily powers.
The hit modifier for AoE of the boss was 20 + d20 against reflex.
The gravity magic were circles on the ground that the boss could place with a minor action. The circles could be dispelled by a DC30 Arcana check. The circles would pull the party towards it with a standard action from the boss and you would have to do a strength check to see how far towards the circle you would be pulled. If you were standing inside of the circle (a 3x3 square) you would be slowed until you leave the circle.
I myself was the healer of the party as a cleric with paragorn path Compassionate Healer. Making me a very strong healer with close to zero damage.