Right, after a little discussion:
To make everything clear - xxxsultanxxxde was a nickname SGuard_Transilsaka (according to SG_Anani it was him) used in the battle. He joined the defending team against the attackers who were from his faction. He then spawned unarmed, was seen running around with no armor and weapon only, and later Vovka from attackers was armed, killing enemies after Transilsaka has disconnected.
According to Bozdag and Lacoste, it was all planned before the battle (screenshots from Blackbows and their chat and messages on c-rpg site), and clearly xxxsultanxxxde was NOT killed, he disconnected.
According to SG_Anani, he didn't do it to help his faction, but he wanted to "take a revenge" and fight against them in this battle, but forgot to change his banner (which he changed between disconnects apparently).
I have to make an assumption, based on the comments here:
That SG_Anani is correct and SGuard_Transilsaka really is xxxsultanxxxde, and that it was a planned action to have him join as defender and sabotage his team.
The screenshots are pretty straightforward - xxxsultanxxxde joined, spawned with weapons, later died to supply the attacking team with weapons. Too many things point to that, even if it was the unlikely case where he just joined, then accidentaly lost connection.
That's why SGuard_Transilsaka is banned for 1 days for strategus griefing. That's a warning - Strategus is back in action, but so are it's rules and they will be enforced.
Common sense and
official strategus rules.