My Stomach Rumbles...

The Basilius should provide enough mana coverage at the beginning. Personally I go for fast Bloodstone which, IMHO, should be part of every Undying build. It's the perfect item for him.

Your current item build doesn't cover up the weakness of having super spammable skills cause there are simply not enough mana regen items.

Bloodstone solves all of Undying's problems. HP/mana pool and HP/mana regen. The ability to continously cast Decay every 4 seconds while having mana to heal yourself with Soul Rip in a prolonged team fight is crucial to helping the team win.

Soul Ring and Vanguard are good early game items but they don't scale into mid-late game items while a Perseverance does.

Well, if you plan on going defensive with level 1 Tombstone, it's fine. But I think it's really a waste of Undying's abilities. Undying is one of the heroes with high first blood potentials. Decay is actually a defensive mechanism as well by draining up to 8 strength in a dual lane. And if you are triple ganked in a solo situation, the Tombstone is not going help.

Cheers

Yes I know,decay is one of the best skills early.But here it goes:If you support somebody,will you get that soul ring fast enough to spam decay early?You need to get wards/the courier and other supportish items(as Undy goes as same as somekind of Tide's build,rushing the Pipe is a good Idea vs a heavy AoE team.

Thanks and I will make sure to remember advice in the future.

OH and actually,level 1 tombstone is amasing for the simple fact that it ruins every atempt to get ganked at lvl 1.IF you see ppl come out from the fog just lay down this baby and watch them run away.

They don't run away because its powerfull,they run away because of the mentality and the chaos it creates and something that is printed in people's minds:That Tombstone is amasing early when fighting in the lane.

+1, I disagree with lvl 1 tombstone but generally agree with the rest of the build and playstle.
Decay is a fantastic skill at lower levels

Decay->Rip->Rip should be standard level 1-3 build for Undying. When everyone is level 1, Decay is one of the best nukes in the game. If lane with disabler, pretty much guaranteed first blood.

Undying is currently bugged at the moment. Decay essentially deals no damage (http://dev.dota2.com/showthread.php?t=44771). Tombstone's Deathlust threshold isn't scaling past Level 1/100 HP either (http://dev.dota2.com/showthread.php?t=44772).

I would recommend not playing Undying at all until he is fixed, as he is significantly less powerful than he should be in his current state.

Keep the comments comming:)