First impressions are meh!
But arching death seems really good when combined with a level 4. However 500 points is a lot for a model who can be canned off pretty easily.
Honestly I would rather just take this model and use the VL rules from the Skaven rulebook. The problem that the VL has always had is that it tries to do too much, doesnt do any of it exceptionally well and yet pays a points premium for it. In a Skaven army 500pts buys you a lot
of stuff, so for a unit to be worth that much it really needs to be appealing, and unfortunately VLs just dont cut it.
Seems more like a Keeper of Secrets than a Vermin Lord. Not really sure about all the variants as well as I
thought it was supposed to be more of an analogue to the Greater Daemons than to a Daemon Prince
There is some Skaven fluff that exists that speculates that VLs are the embodiment of particularly powerful Lords of Decay (the Skaven leaders), and that when a Lord of Decay dies he may become a VL if he was bada** enough during life. I personally reckon GW has just taken this to the logical extreme in the Skaven ET book, and given the clans their own VL to represent their respective Lord of Decay.....
.....or some random Skaven ascend to godhood because why the feth not? Its the End Times!