William Stryker is a former member of S.H.I.E.L.D.. He was the man behind the experiment simply called 'Weapon X.' The X was representing the Roman numeral 10 meaning the individual was the 10th person to go under for the experiment.
The sole survivor of the Weapon X program was later revealed to be named Wolverine.
- William Stryker never appeared in X-Men: Evolution, however the story involving him was told in the episode Grim Reminder.