I suggest reading his ultimate before his other abilities.
Driven by Jealousy
Orophis gains 100% critical strike chance against units with 90% or more health.
Driven by Jealousy is a self targeted buff that is only in effect when certain units are damaged.
Critical Strike change is gained with all auto attacks and Serpentine Strikes against targets with 100% health.
COST: 60 / 70 / 80 / 90 / 100 Mana
Active: Orophis bites target enemy, dealing magic damage in the form of missing health each second for the next four seconds.
Magic Damage per second: 2 / 2.5 / 3 / 3.5 / 4% of targets missing health (+1% per 50 Bonus AD)
Shed Skin: If Orophis' duplicate targets unit with above 25% health, it will continue to chase and attack the nearest enemy unit. If the target has below 25% health, or all nearby enemy units leave a 700 range, it will attempt to flee.
Single targeted ability that applies a damaging debuff
Passive: Whenever Orophis lands a critical strike on a champion, that champion is marked for 4 seconds. Only one champion can be marked this way.
Magic Damage: 40 / 65 / 90 / 115 / 140 (+40% AP)
Slow:22 / 26 / 30 / 34 / 38%
Active: Orophis inspires jealousy in the marked champion, dealing magic damage and knocking back enemies other than the marked champion. The marked champion is slowed while moving towards nearby enemy units and no longer shares and receives vision with allies for the next 5 seconds.
Shed Skin: If Orophis' duplicate would strike a unit this way, it will continue to chase and attack that unit. If the duplicate deals no damage to a unit this way, or if all nearby enemy units leave a 700 range, it will attempt to flee.
Polluted Minds places a debuff on all champion in an area of effect centered on Orophis
enemy units need to be in a 700 range in order to be considered nearby
COST: 90 / 75 / 65 / 50 / 35 mana
COOLDOWN: 15 / 14 / 13 / 12 / 11
Active: Orophis slithers to target location, dodging multi target skill shots and aoe effects. Upon arriving, Orophis deals (+120% AD) physical damage to the closest enemy (prioritizing champions) to the destination. This attack can critically strike and apply on hit effects.
Dash Speed: 1000 / 1100 / 1200 / 1300 / 1400
Shed Skin: If Orophis' duplicate would strike a unit this way, it will continue to chase and attack the nearest enemy unit. If the duplicate deals no damage to a unit this way, or if all nearby enemy units leave a 700 range, it will attempt to flee.
Serpentine Strike is a location targeted dash that deals physical damage to an enemy near the destination.
The physical damage portion has a range of 200 from the destination.
COST: No cost
COOLDOWN: 40 / 35 / 30
Active: Orophis' next spell creates a duplicate to cast it in his stead, meanwhile Orophis becomes stealthed until the duration expires, he attacks, or casts a spell. If Orophis has not modified a spell in this way after 3 seconds, he may reactivate Shed Skin to put it on a 3 second cooldown instead.
Stealth Duration: 3 / 5 / 7
Duplicate Auto attack Damage:(50/60/70% AD)
This duplicate's behavior is different depending on the spell. This duplicate gains no critical strike chance from items, takes 50% extra damage and deals reduced damage with its auto attacks. When the stealth effect ends, the duplicate dies as well.
Shed Skin is an ability modifying, self targeted buff, that can be taken back if the ability has not been used after 3 seconds.
Damage dealt by spells (including serpentine strike) used by the duplicate are not reduced with its autoattacks.
Notes and thoughts behind abilities!
Infest Weakness scales with AD but deals magic damage. Orophis's main damage comes from building AD and auto attacking, while this mixed damage may seem powerful, you must remember that it scales off of missing health, and will only be powerful while executing people.