An idea since we get artifacts from the raid that have siva inside them. We get a search and cleanout mission on the dreadnought to wipe out a bunch of hive and taken that have been pooling up power to bring their numbers up and we get overwhelmed and have to flee kind of like the moon mission with the soul of crota and in the last cutscene, our guardian drops his siva artifact and the hive eventually find it and they get infused with it and come to power because we all need yet another chunk of story pertaining to the hive right?. Couple of pointless missions later we take them out once and for all with the new taken strike boss being infused with siva. Wanna get more lore-ish to back up the april update? SIVA follows commands and the particular artifact couldve contained siva that was commanded long ago to replicate and repair which could lead to giving us the reason to, story-wise, destroy the dreadnought at the end of the strike, clearing out the solar system of hive since they all came to kill you through portals made from the boss which will give way to cabal and vex being our next problem in destiny 2. I already made a siva sword idea for you bungie, hire meh.