Jack is also the founder of the Wizards' Guild. This is said when you help Jack and go back to talk to him in the Part B section of Time. The inspiration of which he talks of is you (your character) for talking to him in Part A.
In the alternate timeline in which the Player was never born (and therefore never inspired Jack to be a good person), Jack grows up to be a psychotic sorcerer druid that terrorises the citizens of Gielinor until his rampage needed to be stopped by Guthix himself, who was forced to kill him. This causes Seren to leave Gielinor with her Elves, and therefore caused Zaros to never arrive, as he was attracted to Gielinor because Seren was on it.[source needed]
Although Jack appears to be knocked back while experimenting with his runes his yellow dot on the map does not move.