My version of Kalista
Passive: Soul's Oath: After 5 seconds, the closest ally within 500 units will be soul bound to Kalista. This bond will only break after Kalista or the soul bound ally dies, where the passive will try to find an available partner again. Kalista gains bonus movespeed when her soul bound uses an ability and vice versa. The teather does not being forming until Kalista begins moving on her base (when the game starts, re-spawn, and recall with no soul bound). The tether can be broken during the 5 second formation by walking out of the 500 unit radius.
Q: Pierce: Passive: Kalista generates one spear ammo every 15 seconds, holding up to 3 spears. Active: Kalista hurls a spear, lodging itself into the first unit struck. Killing a unit allows the spear to pass through to hit another unit.
W: Sentinel: Kalista sends out a ghost for every champion impaled with a spear. If the ghost hunts down a champion, the champion will be slowed 10% for 1 second. More spears, more 10% slow each. Ghosts have 2 hit points, have vision in front of them, and move speed equal to Kalista's total movespeed.
E: Rend: Passive: Kalista's auto attacks impale units struck. Max three impalements on one unit. Impalements last 3 seconds. Active: Kalista rips spears out of all units, returning them to her, dealing damage to all units hit on the way back. If Rend kills a unit, its cooldown is refreshed.
R: Oathsworn: Kalista summons a ghost of her soul bound partner at target location, granting vision, not dealing damage, but slows nearby units for 1 second. Her soul bound ally can click on the ghost (if in a 1000 unit range) to be summoned to that location, knocking up units in that area and deal magic damage.