Trivia

• In Vertigo, It is revealed that he's afraid of spiders.
• William is the newest addition to Team Lyoko, but ironically, on his first mission, he ended up becoming XANA's slave for the rest of the series.
• William is the only one that has a Nav Skid not belonging to the Skidbladnir.
• He is the only male in Team Lyoko that was attacked by the Scyphozoa.
• It is now and forever unknown whether William's costume reverted back to the silver suit or remained black due to his lengthy possession by XANA. Even his Lyoko avatar no longer shows the silver suit he wore previously, which suggests that he may still have the black suit.
• William's Eye of XANA isn't in his eyes like when most other people are possessed; he has it on his forehead, signifying his mostly being under XANA's total control. But when he appeared on Earth, either in materialized form or teleported, he had the sign of XANA in his eyes.
• William produces red ripples upon entering a Tower.
• William became the "cool joker" at Kadic after he got suspended from his old school for pasting love letters everywhere. Even Jim thought he was "cool" and wanted him in charge of the wreck room.
• He's Ulrich's rival, thus, the foil of Sissi.
• He was the only member of Team Lyoko who did not join the others in shutting down the supercomputer.
• William is rejected by Yumi in Echoes, thus putting an end, a temporary one at least, to the romance between them.

William is the first Lyoko Warrior to change his attire, in this case a XANA uniform.