Masked Beast Des Guardius
Group: Fiend
Type: Dark
Level: 8
Atk: 3300
Def: 2500
This card can only be summoned from the Deckmaster position by tributing "Grand Tiki Elder" and any other face-up monster on your side of the field. Once per turn, you may add any card with "Mask" in its name to your hand from your deck (the deck is then shuffled) or move any card that begins with "Des" to the top of your deck.

Mask of Remnants (restricted to 1)
Equip Spell
You can only play this card if "Masked Beast Des Guardius" is your current Deckmaster. When your Deckmaster is sent to the graveyard, you may play this card from your deck and equip it to any monster on your opponent's side of the field to take control of the equipped monster. The equipped monster is considered your new Deckmaster, and cannot return to the Deckmaster position (no effects are added to the equip monster).

Dueling like Lumis and Umbra. ;)
Good idea, and the deckmaster is well-made.

With both the Des- and the Mask-effect, you should restrict the Mask-effect to every second round, as there are really strong masks, and getting them out like nothing would be too easy.
This is all.

Except you should be able to play the Mask of the Remnants from your hand, as well, not only your deck.

The masks, generally, aren't that strong so I don't see why you'd have to restrict it to every other turn. The only thing people would have to worry about is a possible Masked Beast running them down.

I like the Mask of Remnants idea, as it's like extra monster removal on hudge monsters. Slap it with an ATK draining card like Megamoprh, ram it into your opponents monster that's woopin your cards and bam. No more of that monster.

After thinking about it... Masks are really not that strong, you are right.
Still, you get a very good hand advantage(which is, sadly, the case for all of those add-to-hand deckmasters :( ).