New User, 4.e and God questions.

[RangerWickett]

Basically gods in D&D are designed so that final fights against them stand out from every other battle the PCs have been in. You don't just jump in and deal hit point damage until the enemy is dead; you have to accomplish a quest of some sort to make the god vulnerable first.

What that quest is is up to you, but generally it should be something mythically significant to the god in question. You want to kill Tiamat, a greedy dragon goddess with five heads? Well first you have to steal the treasure from her hoard, and give the immense wealth away within five days. The theft itself should give you a good adventure, but the 'getting rid of the money selflessly' part is where the real fun and creativity comes in.

So no, there's no hard rule, just a guideline that, "You cannot kill a god until you've done something that is appropriate to that god's myth."

 

[Squire James]

If you use Vecna's stats as a template for how to give stats to gods, the general idea is that one can only bloody a god and make it go away by HP damage alone. This works out well for most god-slaying scenarios where the god harasses the party one or more times to give them incentive to complete the "god vulnerability quest".

I would also introduce a new wrinkle or two to the god's power when bloodied after being made vulnerable, just so it's not an anticlimactic "finish the god's HP" at the end.