Crystal Girl

Evolution Tree
It evolves from a Rock Spirit when it reach max level. It is a final evolution.

When it evolves it grew one size, gain the Encase and CrystalShard skill, and you can choose one of the following:
 * Level Type Seduction - Learn Entice
 * Level Type Magic - Learn CrystalStorm
 * Level Type Support - Learn HardenSkin

It also evolves from an Ice spirit with a different Support Type skill learned.

Moneymaking
It takes them 5 stamina to produce 1 crystal.

Portal event rates, IIRC, are 200 gold for 5 crystals.

This means a single crystal is worth 40 gold to you.

That's 5 stamina for 40 gold.

For comparison, brothel rates in a basic-type room are 3 stamina for 20 gold, but that's without tips which can more than triple this rate.

However they do not need to occupy a slot in a brothel room to make crystals, nor do they need any training.

But their real financial value comes from by-product use.

When you are using them for fusion, you can exhaust their stamina before fusing and it'll easily cover most of the fusion cost if not all of it.

A "fresh" crystal girl gives you a total of 20 crystals (worth 800 gold in portals).

They aren't spirits however (even though they can be evolved from such) so they will pass on their species genes during fusion which can be a problem (solvable problem, but a problem nonetheless) and they also can't fuse with beasts without a catalyst trait.

The same by-product approach also applies to breeding them for give-away tasks (such as lust genes 5+ characters for brothel).

Do keep in mind however, that they give you crystals, NOT gold, so they aren't actually making you money, only saving you money and they can't save more than you would normally need to spend on crystals.

Trivia
Lives in crystal biomes.