Velmont said:
I agree with RA, imbue seems a bit powerfull. I think teh best comparaison we can have in LEW, is the Soulknife. He can have something similar, but less powerfull and it takes a lot more time to progress. I think what is broken in that pwoer, it is the duration. 24 hours is pretty long.
A lot of things are broken--duration, speed of imbuing, flexibility, progession, and stackability.
Duration--24 hours is huge!
Speed of imbuing--that's like an Artificer with infinite action points.
Flexibility--mostly a problem because of speed of imbuing. Oh, it's a Chaotic Evil Ooze? Axiomatic Holy Oozebane time! Oh, an elf in heavy armour? Brilliant Energy Elfbane! Many weapon abilities are balanced based on not being useful in many cases--you know what will be useful when you imbue on the first round of combat.
Progression--you go from the reasonable +1 to the absurd Vorpal-equivalent +5 at a rate of 1 per level. If you look at standard wealth, assuming that the MC is a moron and uses this on a nonmagical weapon (see below stackability issue) a 1st level MC is creating a 2k item when their net wealth is 13k. Okay, very reasonable. a 2nd level MC makes an 8k item when their net wealth is 19k. I guess that's still okay. At 3rd level, they make an 18k item when their net wealth is 27k. That's getting sketchy. At 4th level, they make a 32k item when their net wealth is 36k. That's concerning. At 5th level, they make a 50k item when their net wealth is 50k. Okay, that's absurd! Also, they're going to be making an item worth a heck of a lot more than this in practice--see below.
Stackability--You can put this on a current magic item for even crazier results. Let's say our level 5 MC or her ally has a +3 equivalent weapon (remarkably easy enough at level 10--a Fighter might even have a +4 equivalent if she's lucky, she has more than enough net wealth). When the MC imbues it, the item becomes a +8 equivalent worth 128,000 gold. For the whole day! Zounds! And if it was a +3 equivalent with only a +1 in enhancement bonuses, a Greater Magic Weapon spell will increase the weapon further. I do not exaggerate when I say that a llevel 5 MC who imbues and then someone GMWs an ally's weapon can create a +10 equivalent 200,000 GP equivalent weapon at character level 10 (net wealth ~49k otherwise). We're talking +3 Holy Axiomatic Whatever-Your-Enemy-Is-Bane Wounding or something similar.