The card seems decent. Decently broken, that is.
Okay, so a 4/3 lifelink for 8 is terrible. However, a card with abilities like these should definitely suck on the battlefield so it can be dealt with easier. The first ability is probably fair. Tapping to almost always draw a card is a good, but not terribly OP ability. If they pay the life, your 4/3 just dealt only 2 damage instead of 4. On a mythic like this, especially a legendary one, it's fine, if maybe even a bit unexciting.
Even the last ability is fine, because it's only relevant in multiplayer, and this makes for a cool incentive to kill people and draw the game to a close instead of turtling up and dragging things out forever. I would suggest that just searching for one card is enough though, otherwise this guy could be a seriously mean combo enabler. Either way, I'm not too worried about the last ability.
On the other hand, the second ability is pretty broken. Sure, they have a way out of it, by eating a DOUBLE LIGHTNING BOLT. EVERY TURN. And if they don't, you get your favorite three things from your whole deck every turn and just throw them on top. That's absurd. That being said, I'm not sure his abilities line up well with his cost and stats. This card is going in a red/black deck, obviously. With both of those colors' access to removal, burn, and fast aggro creatures, it will be very easy to get your opponent down to around 10 life, which is when they won't be able to take 6 damage just to stop your ability anymore. It's weird though, because this guy costs SO MUCH that most red/black decks will never cast him before they end the game. So I don't know, ultimately, but this card seems abysmally strong, even if his body sucks.