Transcended Onyx weapons and abyss in this game are compatible with transcended spirit stones from the cash shop mall only as it wouldn't make any sense having a onyx weapon with 5x% damage drop stacked with a in game spirit stone damage drop resulting with 8x% Damage drop combined. Many free to play players stick to ferkhan/opaniel/T-Opaniel/Igniel T-Opaniel since Keena spirit stones work on them and give a pretty good balance of stats for pvp/pve. I really don't recommend a trans onyx or abyss weapon unless your a support character like a priest that needs as much damage drop as possible and pvps often.