Deckard Cain is simultaneously one of the most recognized names in the Diablo franchise and the most unlikely face you would expect to see in a 5v5 brawl. However, this does not stop fans from desperately wanting to see the scholar in the Heroes of the Storm roster.
Deckard Cain is most known for his near infinite wisdom throughout almost all of the Diablo games. Cain dedicated his life to studying the nature of the angels and demons that found themselves at odds with the mortal plane. As such, players could visit Cain for any additional insight into the rich lore of the game. While he lacks combat abilities, Cain uses wisdom as a weapon.
In terms of his role in Heroes of the Storm, Deckard Cain would be a decidedly interesting character to see act as a support. Due to his lack of fighting experience, Cain can likely use his research abilities to aid his allies. Whether it be giving insight into the weaknesses of adversaries or offering improved "loot" to friends, Deckard Cain would be one of the most unique additions to the Heroes of the Storm roster.