ThanatosVI
Headphoneus Supremus
The only thing I would caution about is matching a warm DAC with a warm amp to drive a warm headphone. That warmth and distortion will carry from one to the other and may color the end sound more than you expected or wanted. My advice is to start with the headphones and work back to the DAC. That will help you fine-tune the sound a bit more. With the flexibility of tube-rolling to alter sound, you may find that's enough to dial in the sound you want without worrying about a DAC at all. Plus, the DAC will almost certainly do the least to change the sound.
The Empyrean is quite warm
The Mjolnir isn't overly warm.
Maybe considering that the current Gungnir revision being less warm than the older one isn't a bad thing in the end.
Thx for the advice.