nerf Magenog

Magenog is incredibly broken. for 2 of each color, you get an invincible wall that keeps on regenerating. if said wall is destroyed, any other monster replaces it. NPC costs 10, and can be killed by any effect that doesn't target. the good Tsuitachi Ninja costs 4 and has no attack and can be killed by any direct damage. Magenog can be played on turn 2 and give you a Tsuitachi Ninja with a decent attack power that is even harder to kill. how is that not broken?