and yet again a minor notice: the invulnerability in ancient vampire armor works only once, then you need to drop it and pick it up again to make it work. What im suggesting is that you remove that item and create a 1 use item (non-stackable) that would give about 5-10 sec invulnerability. Here is a little example about what i think:
Item: Orb of Immortality.
Use: <insert lenght here> Invulnerability, 1 use only.
Effect (in inv.): 10 armor, 5hp reg.
Cost: 40 gold.
'This orb was created by blah blah blah blah blah...
By crushing it by your bare hands you can unleash the power of immortality inside, but only for limited time.'