Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight

Legendary Creature — Elemental God

Flying, lifelink

Creature spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a creature spell pays for {1} or one mana of that creature's color.)

At the beginning of your first main phase, you may pay {B}. If you do, transform Eirdu.

Legendary Creature — Elemental God

Flying, lifelink

Each other nontoken creature you control has persist. (When it dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

At the beginning of your first main phase, you may pay {W}. If you do, transform Isilu.