J'zargo was a fellow classmate of Crotch's in the College of Magic, and was S'oggy's brother, but he could never the latter. Crotch killed J'zargo during the episode "Crotch vs Winterhold", where he kills everybody in the College of Magic.
Season 2 Edit
J'zargo was a student in the College of Winterhold, and was a friend of Crotch. He had a habit for sitting in other people's chairs, which was the reason for Crotch murdering him in "Crotch vs Winterhold". Crotch brought his corpse home to remind himself of the 'good old days in college'.
Season 5 Edit
J'zargo was S'oggy's older brother, a cat who always made everything a competition. When S'oggy set out to the Companions, J'zargo left for the College of Winterhold, which was strange for most Kahjit. S'oggy made it his goal to somehow impress his brother, and would visit him frequently, however he was never worthy, even though he managed to be both Leader of the Companions and the Thieves Guild, plus have a hot girlfriend.
When S'oggy learnt that all skooma had run out, he went to the College of Winterhold, to tell his brother. There he found a book, written by Crotch Guzzler, which stated every name of every person that he killed in the College. On the final page, it said J'zargo's name. S'oggy then became fierce for revenge, and went to kill Crotch, assassinating his family in the process to show how it feels to lose some one.
Eventually, S'oggy made peace with Crotch, Fün Tits and Cock Nibbler. However, when S'oggy least expected it, they began firing crossbow bolts at him. Eventually, S'oggy knew he was dying, and saw the ghost of his brother. He asked if he had finally made his brother proud, but all J'zargo asked was 'have you mastered the expert level destruction spells yet' (this was J'zargo's goal) and when [S'oggy replied saying 'no', J'zargo left, and Crotch shot S'oggy one final time, killing him in the process.
J'zargo's relationship with S'oggy was slightly complicated. S'oggy obviously greatly admired his older brother but J'zargo often looked down on him and ignored his accomplishments.
J'zargo seemed to be unaware how much Crotch utterly loathed him, on one occasion saying that he felt "warmness" from Crotch presence. Crotch brought J'zargo's corpse to his house to aid him in giving his children life lessons.
Not much is known about Tolfdir and J'zargo's relationship but Tolfdir did not make any attempts to apprehend Crotch after he killed J'zargo. Tolfdir also defiled J'zargo's corpse by sitting on it.