It’s weird that Valki can only change forms once, but here we are anyhow. This is actually an interesting card. This color pairing is hardly the best for ramping, but being able to play Tibalt even once is very strong. If Tibalt dies, that’s not really a problem.
The actual problem is that I don’t really know what to do with this particular commander. I just don’t see a specific direction. The abilities on both sides make this even more difficult, as it’s so dependent on what your opponents bring to the table. With this specific combination of colors, I would just like to start by a) playing all the cards I like that are in this specific color combination and b) try to sow some chaos (which is what this color pairing does best).
There’s a bit of a discard theme there, so let’s push that a bit:
Oh, wow, that’s already 42 cards, which leaves room for 17 more (assuming 40 lands, which I think is adequate). I do want around 10 ways to find more lands to make sure everything goes fine. On top of that, some interaction:
And our ramp:
I didn’t check the curve in any way and there are some very expensive cards there. The idea is to slow down your opponents with the discard and handle card advantage with Tibalt. Some cards like Read the Bones would be great, but we can manage without it.