>>56599686There are different versions of the myth that have the giant(s) (kyojin) be different. One version has them the fragments of Arceus' egg, while other versions like the one in OP be a later creation of Arceus.
>>56599948this version has the unnamed giant being a part of a trio with dialga and palkia, associated with destruction, which sounds the most like giratina. it dies, becoming the weather trio. giratina doesn't seem to have fully been realized until quite late.