Togekiss's design appears to draw inspiration from fairies and birds. Its association with peace and joy, as well as its white coloration, suggests inspiration from doves, but its soaring flight and some physical aspects are similar to those of large birds of prey. Togekiss may have also been designed to resemble a flying wing.
Yeah, doves are pretty peaceful as it is - hence the 'kiss' I guess. All of it's Pokedex entries state it's only seen where there is happiness and all that, no strife. Also, of course, it could be based off a fairy, who got a Fairy-type later in the game. It may also seem like a 'broader' version of it's pre-evolution Togetic, who are roughly similar to each other. Again, it's origin according to Bulbapedia is:
Togetic's design appears to draw inspiration from a fairy, a baby bird, and an egg.
By baby bird, Togetic's Japanese romanization is Togechick, ending with 'chick' which means baby bird.
Togekiss is one of those Pokemon that don't have a very distinct design, but it could just be a bigger and better version of pre-evolutions Togetic and Togepi. It's still safe to say that Togekiss is based on a peaceful bird, like a dove.
Hope I helped. :)
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