[hotspike18]

In a recent game of mine, an opponent brought two units of Blood Claws with Drop Pods, but in order to have them both come down on turn one, he purchased one for his HQ unit as well and simply elected not to deploy them in it, it came down empty but gave him the math he needed for the Drop Pod Assault rules. I can't think of an off-hand way to negating this, so I may just be whining in the end, but I wanted to check with you guys...

Can he do this legally?

 

[Red Archer]

Yes, it is legal. (If the units all had the option to buy a drop pod as a dedicated transport.)

Drop pod assault says half your army's drop pods (rounded up) are required to perform the drop pod assault (come down on turn 1). [Codex: Space Marines, page 69 - don't know the page in Codex: Space Wolves right now, unfortunately.] 3 drop pods, half is 1.5. Rounded up: 2 drop pods perform drop pod assault.
Any transport may be deployed and/or kept in reserve either empty or transporting a unit, in case of dedicated transports only the unit they were bought with. [Big rulebook, page 94.]

It is not obligatory to have units embarked in transports when they are deployed, not even in dedicated transports and not even in drop pods. It is a very viable tactic to drop them empty, though a bit cheesy to buy a third one that will always drop empty just to be able to drop two other ones on turn 1. Consider reserving everything as a counter.

 

[Wolf Guard]

Did he just have a dedicated transport for his HQ? Because there is no Space Puppy HQ that can take a POD, unless he is attached to another squad.

 

[jy2]

He said HQ unit. I'm assuming his HQ was with a unit that could get a Drop Pod.

 

[hotspike18]

Honestly I couldn't say for sure, but I think it was Njal Stormcaller (spelling) with Wolf Guard(?) squadmates? Thanks for the replies guys.