Saero'd, Undead

Saero'd, Undead
HP 549
Mana 299
BAT 1.4
MS 305
HP Regen 1.5
MP Regen 1
Armor 5
Damage 69-72 (Melee)
STR 21 + 2
*AGI 26 + 4.8
INT 23 + 1.8

Lifeleech
20/30/40/50% Lifesteal
Non-orb, stacks with other lifesteals

Unholy Power
40/80/120/160 AS
20/30/40/50% Movespeed
5/6/7/8 seconds
25/22/19/16 sec CD
90 Mana

Flesh Rip
7/10/13/16 AS and Damage per 5% of the target's missing HP.

Risen From the Grave
Magic Immunity
20/30/40 Armor
Immune to death
20/25/30 seconds
140/120/100 sec CD
200 Mana

Interesting. What did you have in mind for his aesthetics? What does he look like...

Also, to make his first ability more unique, and make the name mean more, how about instead of just adding life-steal, it slowly drains an amount of the targets health and gives it to you over a few seconds. For example:

Lifeleech
Orb attack/Auto-cast
Unique Attack Modifier, but stacks with Life-steal
10/15/20/25 life steal per second
3/3/4/4 second duration
Costs 20 mana per cast
Lifeleech stacks with other Life-leechs currently taking place.

This would mean it would damage them and heal you for 30/45/80/100 for every attack you make. The mana cost would be nothing end game, but stop him from spamming it early game - 15 attacks still does 450 damage at lvl 1, not counting damage from you attacks, you it would be a great lane control ability.

Now, is Flesh rip a passive? It looks incredibly OP to do 150 extra damage and 150 attack speed when an enemy is on half health. While it's constantly getting faster? While draining huge amounts of health per second? Seeing as there is life-leech and a powerful ability + ultimate that give attack speed, i think a new ability should be made, something different to complement his ravenous life-draining attacks. Perhaps something Necromantic?

Next, his ultimate. Even with an 100 second cool-down, 30 seconds of magic immunity is a joke. In that time, he could easily sprint around and earn a rampage, then destroy all the towers uncontested, before retreating to the jungle to farm until the cool-down if off. I would say half both the cool-down and the duration.
5/10/15 second duration and 90/70/50 second cool-down is much more balanced, as it gives the enemy team a chance to use magic on you in a team-fight.

Lastly - You haven't specified whether this hero is ranged or melee. I can see he is agility, but that could be either. Lifeleech, and his name, shout undead floaty ranged mage/warlock at me, like a grey-skinned Undying/Lich, but Undead Rage, Flesh rip and Undead power all sound incredibly akin to Life-stealer, who is melee. Be careful with your decision of which one it is, as it may end up too similar to Life-stealer...

wow, this guy will just latch on to one guy and dominate. and in late game he can literally 5v1 with his ult and rediculous lifesteal.