Raika VS Vaylantz

[winged jetty]

So I have a question on what is the difference between the raika links and Vaylantz Genesis Grand Duke

Vaylantz Genesis Grand Duke effect that matter here is : If this card is Special Summoned: You can target 1 Monster Card in your opponent's Spell & Trap Zone; return it to the hand, and if you do, inflict damage to your opponent equal to its ATK, then, this card gains ATK equal to half the damage inflicted.

If you use its effect on an extra deck monster in the s/t zone it doesn't burn since the monster isn't returned to the hand but to the extra Deck.

The raika links all have this effect: You can target 1 Insect, Plant, or Reptile monster you control; place it on the bottom of the Deck, and if you do, Special Summon this card

You can use that effect on tokens or monster that get banished when they leave the field and the monster would be banished or the token remove and the raika link will not summon itself cuz the monster haven't been placed under the Deck. But you can use this effect also on an extra deck monster and the link will summon itself back even if the monster haven't been placed on the bottom of the deck but extra deck.

So why does it work with the raika but not Grand Duke? Is it because one is hand and the other is Deck, do raika treat extra deck as deck for this specific effect?

[pallid basin]

Generally, when returning a card from to the deck, returning it to the extra deck meets the requirements too. See "Dreaming Reality of Nemleria, Realized" (https://db.ygorganization.com/card#18802), Chaos Space (https://db.ygorganization.com/qa#23089) or Branded Regained (https://db.ygorganization.com/card#17808)

For the Vaylantz, as you suggested, because its attempting to return it to the hand, and it goes to the ED instead, it did not meet the requirement, thus does not get the whole effect.