This game split from crossfire and after 2 years development a first full playable BETA has arrived.
The engine offers nearly all concepts of modern online rpgs:
mob aggro ranges, buffs/debuffs, mob pulling, factions, object scripting in python, active target system, item quality & conditions (repair/smithy), resistance/protection system, server sided AE (area effect) spells, skill exp, client sided throw/range control system, group playing, cooperative PvE maps (player can't hurt/block other players), PvP maps (player vs player), permdeath maps (player stay dead on maps until another player resurrect him)...

License: free

Additional System Requirements: SDL & ogg/vorbis