(New) Elemental Dragons and Creature Swap

If I used a Creature Swap on one of my Elemental Dragons (assuming it was special summoned), would it return (at the end phase of my opponent's turn) to my opponent's hand? Or would it return to my hand?

To your hand...of course...That's too obvious :D

Also, which Elemental Dragon effect can only be used once per turn? The adding to hand, the special summoning, the discarding, or all 3? <_> I never understood cards like that.

That depends on the card's text e.e The truth is I haven't taken any research about this archetype so...yeah ._. Basically if the effect says "Once per turn", the effect will only be used once per turn.

Example:

Wikia:
Blaster, Elemental Dragon of Calderas
*******
2800/1800



What the Condition says is that you can only activate one of the 4 effects of this card.

1.Ignition: You can banish 2 Dragon-Type and/or FIRE monsters from your hand or Graveyard, except this card; Special Summon this card from your hand or Graveyard.
2.Trigger: During your opponent's End Phase, if this card was Special Summoned: Return it to the hand.
3.Ignition: You can discard this card and 1 other FIRE monster to the Graveyard to target 1 card on the field; destroy that target.
4.Trigger: If this card is banished: You can add 1 FIRE Dragon-Type monster from your Deck to your hand.

Condition:You can only use 1 "Blaster, Elemental Dragon of Calderas" effect per turn, and only once that turn.

You can activate ONLY ONE of the effects listed above, and only once per turn.
Hence the returning effect applies during the opponent's turn.

Anus gets the thumbs up for the awesome answer.

Locked~~