champion idea javen

Name: Javen

Gender: Male

Role: Assassin/Mid Laner

Secondary bar: Mana

Melee Auto Attacks

Passive: Reckon Pain Upon dealing 20% of his opponents maximum health in 2 seconds his next ability within 3 seconds opens a vital spot slowing the enemy and dealing 3/5/7/9% bonus magic damage (Scaling by level 1/6/11/16)

Q: Cursed Blood Katana Passive: All of Javen's auto attacks apply grevious wounds if the champion has 40% or less health

Active: Throws his katana in a straight line up to 700 units dealing 75/100/125/150/175 of attack damage and Marking enemies for 5 seconds (javens basic attacks consume the mark dealing 10/20/30/40/50 bonus magic damage using 50/60/70/80/90 mana per level

W: Culture of Death Active: Taunts his enemy and hardens his robe increasing his magic resist and taunting targetted enemy champion for 5 seconds 5/10/15/20/25 magic resist and 30/45/60/75/90 mana per rank

E: Peek into Hell Shows targetted enemy champion a gate into hell dealing 30/40/50/60/70 magic damage per second for 3 seconds and using 90/85/80/75/70 mana per rank

R: Unholy Grasp Sends a dark arm at an enemy which travels up to 1000 units if it hits an enemy champion with deal 200/250/300 magic damage per rank using 100 mana at all ranks and slowing them for 3 seconds

Tell me what you think of this champion idea and if it needs a nerf a buff or if its balanced (first champion creation of mine)