Thank you.
So i mute non magical item with essence? Or magic otem with essence? Or two magic items?
Hopefully this helps:
You use essence with an item of the same tier and ideally the same stat quality. This rerolls all of the stats of the item to completely new stats.
E.g.
For a level 30 dagger with +4 stats:
If you use a level 30 essence, with +2 stats, you will get a level 30 dagger with +2 stats.
If you use a level 30 essence with +4 stats, you will get a level 30 dagger with +4 stats.
If you use a level 30 essence with +7 stats, you will get a level 30 dagger with anywhere from +4 to +7 stats.
There is also a chance the item juat randomly gets destroyed with the essence.
Also note the essence tier for, e.g. level 10 will say V but will say skill rank level 20 due to I, Ii and III being 1, 5 and 10, so just subtract 10 from skill rank level to get the right essence for an item.