Summary: Have you made up your mind about which Fire Hero to use? Now you need to decide which Earth Hero.
Personally, I thought both Jirva and Arlei had its own pro and felt the choice was really dependent on your deck style. But Jirva was indeed more popular card. So Sony made following change.
Race – Hero
Affiliation – Hammer Valley
– Archbisshop Jirva adds your current mana to his attack.
– While Archbisshop Jirva is on non-Earth field, you gain 1 mana during your reosultion phase.
(A) Any 1 (C) None (B) S
Comment: Considering the Jirva’s baseline health of 5, placing him on Earth field and gaining Mana every turn indeed may be a bit of overpower (?).