He has strong spells that are semi-spam-able , most people play him as a support though it’s better as semi-support because he needs Aghanim’s scepter very fast, with it his ultimate Ice Blast will dominate enemy heroes and will own them in almost every fight.
best combos: heroes with global ultimate like his (zues, spectre, nature prophet, .. etc) aoe spells like (venom, tide, dark seer …etc)
counters: any Hero with magical resistance ( anti-mage , pudge ,rubick..etc) weaver or terrorblade ultimate counters it, items like :pipe bkb, heroes with high magical damage like lion / lina will own him.
scepter effect : Increases frostbite duration, Duration: 17 second
very Strong ultimate vs squishy heroes.
Spells with long range and scouting spells.
The best counter for healing heroes (alchemist, omni knight, dazzle, void,...etc) .