Dude, I just had a 3 times fused bone dragon in Heroes of might and magic get owned in one shot because of the random fire attacks.
That is precisely why I like my dragons alive.
Two of my monster companions in Tales of Symphonia: Dawn of the New World trump that dragon.
Take my good friend Onyx the Bakunawa (A light elemental Dragon). When he reaches higher levels, he will trash everything. A Wonderful Lure tank in the making...
Emerald, My old Blade Rex who was able to trash almost anything without dying. 9999HP 999TP Over 6k P. ATK. Even in Gladsheim on mania difficulty, he was the last to go down if my party happened to lose.
And that was only because of enemies being 250+ in level when Emerald was capped at 200. His save file was unfortunately... overwritten. May he rest in peace.
As for your Slifer...
- Slifer's Effect:
I see your Slifer and raise it a Delinquent duo and a Rainbow Dragon. Slifer loses 2000 ATK, and with a 6 card hand limit, that puts it at 4000 attack at best (Without the card infinite cards in play). Rainbow dragon could use its effect to send all crystal beasts to the graveyard and gain 1000 ATK for each one sent. Even one sent would mean Rainbow Dragon wins at this point. If you have infinite cards out and more than 7 cards in your hand, I also raise you a morphing jar (before the delinquent duo of course), although slifer's effect kills it after its effect resolves. And to think, the horrors that gravekeeper's servant can cause to an attacking slifer. MY SLIFER ATTACKS YOUR BLUE EYES WHITE DRAGON!!! (4000 ATK) *Discards a card due to gravekeeper's servant dropping slifer to 3000. Opponent reveals rush recklessly* OH SH-- Slifer: 3000 - 3700 :BEWD(A common abbreviation for our famous friend the Blue Eyes White Dragon). The Blue Eyes White Dragon Wins and deals 700 battle damage to the controller of Slifer.
Onto waterknight's references.
Shenron (Earth's Dragon) may have looked evil and possibly could have been evil, but he did not look undead by any means. Perhaps the evil look came about because of the fact revealed in my statement about the GT reference.
Now onto the Dragonball GT reference.
They aren't necessarily undead. They are formed from the evil energy that appeared due to all of the good wishes the heroes made on them. The dragonballs were only meant to be found every 100 years ( or was it 1000?), and thus the evil energy built up within them faster than it could dissipate eventually to bursting. The seven shenrons hatched from them as the dragonballs became full of the evil energy.
Haze Shenron (The Two star dragon) polluted the air around him, that makes him about the closest to an undead as there is always something that is undead that is emitting some pollutant gas that hinders enemies around it. His rather colorful personality suggests he is full of life however
They were evil, but not undead.
The point is, I have not seen an undead dragon that has a lot of staying power.