Blood Remembers

While transformed by Polymorph, the caster retains the inherited racial powers of their original body. Its mana, racial spells, senses, resistances, and racial feats remain active alongside those granted by the new form.

A human in drow form therefore keeps red mana and can cast their learned red spells while also gaining the form's blue mana and racial Psychic spells. Red spells still use their normal components; becoming a drow does not turn them into Psychic spells.

When two colors of mana coexist this way, they use one shared slot reserve. The new form adds another color, not another set of slots. Each slot can fuel a spell of either color, and a slot spent on a red or blue spell is gone from the same shared reserve.

This feat overrides a form's normal loss of racial powers and its restrictions against casting the original body's spells. The caster can still end Polymorph normally.