True king of all calamities ruling question

[s.nickid]

My opponent while attacking used True king of all Calamities and called earth to change all monster card on the field to earth attributed, and all opponent's monster card with that attributed cannot activated their effect this turn, and I know it include activated from graveyard, since my pyramid turtle was still earth in the graveyard because that his pyramid turtle original attributed, during that same turn, he attack my face-up sangan and it become earth attributed while face-up on the field, and then when my sangan got send to the graveyard it would return to dark attributed, so would I be able to activated the mandatory effect of sangan?

[Vennominaga]

Calamities change attribute on field and prevent activation of monsters of that attribute in their opponent's possession. So when card changes location, it is treated as new card by definition so sangan will activate if destroyed because it is dark monster at that moment when it triggers. However, pyramid turtle is earth so it won't be able to activate because being in gy is in possession so activation is prevented.