Complex sentence: He is considered the best "Super Smash Bros. for Wii U" player in the world, with a record-breaking 56-tournament winning streak in 2015, where he won several high-profile tournaments like EVO 2015 and The Big House 5.
Split into simpler sentences: He is considered one of the best "Super Smash Bros. for Wii U" players in the world. ZeRo had a record-breaking 56-tournament winning streak in 2015, in which he also won several high-profile tournaments like EVO 2015 and The Big House 5.