Xerath & Pyke Synergy
Xerath Mid and Pyke Support win 52.8% of 2,138 Low Elo games together, +1.4 points vs expected, 2-patch window 26.19-26.20.
Researched on LoL patch 26.20. Tips are written to hold at any rank; stats come from Low Elo ranked games up to patch 26.20.
Why this duo works
Pyke can start a pick with Bone Skewer(Q) or Phantom Undertow(E), letting Xerath follow from long range with damage and a second stun. Pyke's Death From Below(R) also gives bonus gold to an assisting ally, which can speed a mage's midgame spike.
Playing the duo
Pyke's Bone Skewer(Q) pull and Phantom Undertow(E) stun can hold a target in place for Xerath's Arcanopulse(Q), Eye of Destruction(W), or Shocking Orb(E) follow-up.
When an ally assists Pyke's Death From Below(R) execute, Pyke grants that ally additional gold; player discussions describe this as a way for a mage paired with Pyke to reach a midgame spike faster.
How to play as Xerath
Follow Pyke's hook or stun from range, then use Shocking Orb(E) to extend the catch rather than walking into melee range. Let Pyke's execute resolve when it is safe so you can collect the assist gold.
How to play as Pyke
Look for catches when Xerath is in range to follow, and ping before committing so he can line up Arcanopulse(Q) or Shocking Orb(E) from safety.
Sources
These notes come from r/pykemains, checked against the champions' abilities.