Is Death-blade really good?
I mean its power is 3000 (power attacker +4000) double breaker but it can be killed easily with tornado flame or monsters higher power. If there's A Toel in the field then thats a different story.

What's its mana cost?

it was 7 for death-blade beetle.

That seems way too expensive to me, to get killed by something like Brawler Zyler.

Deathblade beetle only costs 5 mana. It's 3000 power makes it killable by Tornado Flame though.

Meh, I wouldn't bother, but that's just me. Even if it is a power attacker, it still wouldn't last. I guess you could go either way on it, your call.

i traded my beat-blade beetle for a deathliger just for the ability of beath-blade adn deathliger is better 7* for a 9000 power

Death-blade beetle isn't that great... A lot of low cost monsters can take him out.