Not much is known about Vandred, mostly because he exists as a name for an existing generic model in the 6th edition of the game. His blessings included four arms and a snake body, something he shares with Dechala. Due to his skill he was chosen to represent Slaanesh's forces in
ArchaosArchaon's army before he was killed by one of his subordinates and a fellow name for a generic model, Styrkaar of the Sortsvinaer. Styrkaar was made his replacement, and Vandred has become forgotten both in and out of universe. Vengeance would be his in a meta sense however, as Styrkaar was retconned along with the rest of Storm of Chaos. Sigvald replaced them both, even ending up with Vandred's "the Magnificent" title.
He's a generic model, he's whatever you make him.
Total War Warhammer
The leader of the Alghol tribe, a generic Norscan faction in both the Vortex as well as the Mortal Empires campaign, is called Vandred, although with the title "of the Winter's mist" instead of "the Magnificient". This may still be a nod towards original Vandred, since the settlements that are inhabited by the Alghol faction also bear names that could be interpreted as an implication of Slaaneshi worship, e.g. Palace of Princes, with "Prince" being a title not commonly used by Norscan tribes save for the case when they invoke the Serpent, aka Slaanesh. However, given the obscurity of the Tabletop Vandred, it is more likely that Creative Assembly simply stumbled upon the original Vandred while searching for names for their Norscan faction leaders and used it for a generic Lord after realizing that Vandred himself is basically a "non-character" and thus not eligible for adaptation into the game; so most likely, it is just a reference to a forgotten character and he will never make it into the game in his proper form. Although, the whole "character without any noteworthy lore becoming a Legendary Lord despite there being tons of more important characters that should be implemented instead" definitely has precedence in the TW:Warhammer games so far...