Passive:The Darkin Scythe
You collect "souls" if your bar fills up you get to choose if you go Darkin or Shadow assasin.You have a 4 minute couldown on one if you unlocked the other if you get your last "souls" from a ranged champion you can turn Shadow Assasin or if you get it from a melee champion you can go Darkin.

Q:

Reaping Slash
You dash forward and do damage in a cicrcle around you.Good to clear Raptors Murks and to farm with.
In Darkin form your Reaping Slash's damage is increased 50% AD (+ 5% (+ 4% per 100 bonus AD) of target's maximum health).+55 DMG against monster camps.

W:

Blade's Reach
This ability is good to start a gank with you slow your opponent for by 60% for 1.5s decaying.Usually start jungle camps with this ability.
In darking form you have a 1 second knock up.
In Shadow Assasin form it has increased range by 200 and +10% Bonus AD and slow decayes in 2 seconds.

E:

Shadow Step
This ability lets you walk trough walls for the first 1.5 second if you reach a wall and not in combat your time is increased to 5 seconds that you can spend in the walls.And it heals for:100 / 115 / 130 / 145 /
In shadow form you have increased Movement speed by 70% and increased slow resistance.

Preferable: Raptors->Red->Murks->Blue->Krug and then make a gank mid or bot.
Second option: Blue->Krug->Murks->Raptors->Red->Krug its Gold efficient and can gank top or mid.