If you have blue blood, that's all you can donate to these guys.

[{Galvantula}]

Blue-Blooded oni ([url="http://yugioh.wikia.com/wiki/Blue-Blooded_Oni"]http://yugioh.wikia.com/wiki/Blue-Blooded_Oni[/url]) deserves an archetype. Or at least a small one.

Blue-Blooded Ogre
DARK | Rank **** | Zombie/Effect | 2300/1700
This card can not be destroyed by card effects or by battle while it has Xyz Materials. When this card's Xyz Materials are detached by another monster you control: you can add 1 Zombie-Type monster from your Deck to your Hand.

Blue-Blooded Ghoul
DARK | **** | Zombie/Effect | 1000/1200
If this card is detached while treated as an Xyz Material: you can send 1 Zombie-Type monster from your Deck to the Graveyard. Once per turn: You can detach 1 Xyz Material you control; add 2 Zombie-Type monsters from your Graveyard to your Hand. Those monsters can not be Summoned during this turn.

Blue-Blooded Zombie Tiger
Dark | **** | Zombie/Effect | 1600/900
Once per turn: you can detach 1 Xyz Material you control; destroy up to 2 Spell or Trap cards on the Field.

Blue Blood Donation
Normal | Spell
Send 1 "Blue-Blooded" monster you control to the Graveyard; Special Summon 1 Zombie-Type monster from your Hand with the same level as that monster.