The Gemini Craze Coninues [Gemini Mercenary]

[Kingdom Xathers]

This card is treated as a Normal Monster while face-up on the field or in the Graveyard. While this card is face-up on the field, you can Normal Summon it to have it become an Effect Monster with this effect.
* This card can attack twice during each Battle Phase. If this card attacks a second time during the same Battle Phase and destroys a monster by battle: You can add 1 Gemini Monster from your Deck or Graveyard to your hand.

[Therrion]

<3

I really like it, the speed in both the Battle Phase and the search really helps. The search is really balanced, as you'll probably only ever get it once, which while saddening, is fine. You could go the "When this card inflicts Battle Damage to your opponent:" route.  You could also word the first part into a Kachi Kochi like effect, making sure it won't attack twice directly, as lately double attackers have been replaced with this: "If this card destroys a monster by battle and sends it to the graveyard, it can attack once again in a row."