Runes & the 3 attack skills
Out of lightning, gaia and poision, which one has the biggest priority of being developed (mostly in PvE, but to some extent PvP as well)? Also, seeing how hardly anyone has Rot in their builds, is it not worth the investment?

Those 3 skills are must imo. Poison can make stealth chars unable to go dodge/camo, gaia can halt the enemy, lightning is the strongest.

use 5 skill.. u become a killer rune^_^

I think I misread a bit, since I use outdated info to put my questions. What I really meant is, how come noone uses instant damage in their build (I guess that's the one, its ofc only)? Also, what diffrence does poisoning (not poison, but the effect) matter when most officiators die from stealthed sins/archers anyway? Also, finally, in what order of importance does those 4 skills come in PvE. Should I max one, or should I keep (at least the 3 regular) at similar levels?

I would stick with lightning and poison when lvling because some monsters in your pull tend to resist gaia, which then spreads all the monsters out. Some players like instant damage because you don't have to charge, but it has a longer cooldown than magic missile, so I prefer magic missile. Poison helps if they fail to 1 hit you or other player near you. So they have a great chance of being killed because they can't hide. If you have any other questions, feel free to PM me.

^^

what those 5 skill 4 rune..??