ToME: the Tales of Maj'Eyal

I've just found Dethanc.

So now I wonder, is it worth the trouble of losing all benefits of my homemade Vampiric longsword (*Defender*), namely (Wis, Dex, Con, Stealth +6), (life +120%), levitate, see invisible, regenerate, free action and 6 resists to level it up?

Also, if I find more daggers of the set, will I need to grow extra arms to equip them, or is just having them in inventory sufficient for set bonuses?

Not really. They're neat, and while they can theoretically get some really cool tags like flying and even precognition iirc, you've got much better chances of actually finding the ring of precognition than that happening. They tend to gather a lot of low level resists you need immunities to anyways, worthless abilities like flame aura or orc telepathy, and the brands aren't all that helpful when the base damage is a 1d4. Artificers can cheese out way better items.

You need to wield them all to get the set bonus (Which is weak anyways I think.) I think possessing a multi-limbed monster is the only way to do this, since casting arm mimicry twice just extends the duration.

To get the set bonuses (which aren't really all that great) you need to have extra arms from Mimicry, Possession, or the Scroll of Deincarnation (just another form of possession).

The thing about sentient weapons is that they can ridiculous +to_hit and +to_dmg bonuses... for the daggers you'll want to Enchant to (+9,+9) or so before starting to level the weapon. Sereghatol can get insane because it already has ridiculous starting +to_hit and +to_dmg.

If that's worth +N% life (etc.) is a different matter.

PS: Try possessors when become bored with alchemists. They're incredibly fun!

Yeah, forgot about the plusses being their main draw, especially if you can get tons of extra attacks. Still nowhere near the advantage of an alchemist cheesed sword. Vampiric effect alone is worth +50 hit and damage in my book, never mind 120% bonus life.

Cursed is right about the set bonus thing. Mimicry isn't enough -- you need to possess a monster with 3 sets of arms and IIRC there are only 2 of those.

This is one of the reasons why I've dropped their rarity from 100 (i.e. incredibly rare; compare Ringil at 120 or the Crown of Gondor at 40) all the way down to 5. They're neat artifacts, but very rarely game-changing; generally Maedhros is a trade-up, and it's guaranteed in the orc caves.