Theoretically Jerick really has no reason to continue the Gambit. In any case if your House has suceeded with its goals in a gambit it can simply leave the gambit successfully without losing assets. That is if no one else tries to stop them.
Also basically what Jerick said. The Knight has been ordered to do something, whether he actually does it is an entirely different matter. With that being said once the gambit begins neither Hounds nor Knight will be active, they might be close by and they might be watching but for now they are merely observers in a conflict which is unfolding on the mortal level. That is if we find anyone somewhat coherent enough to decide which of the Maddening Mindwarping Horrors from space to worship.
As for the Obelisk. Imagine you having no concept of writing, masonry building, gods, magic or anything beyond your immediate body, those others of your kind and maybe your direct surroundings. And suddenly a massive black pillar shoots out of the ground, it itself glowing with maddening foreign swirls which you can't make heads or tails of yet somehow they still invade your mind to force you to understand the Truth. That you are nothing but an insignificant being in a Universe created by these monstrous beings, that you are but a speck in existence, and that you have been created on a whim, that you could be wiped out by the casual flip of a finger as these divine beings argue about who you have to apparently thank for your existence although its clearly warped into your mind that it was one of them, who hasn't done all that much beyond creating you. Add that to the rest of the ongoing situation and theres your explanationa s to why that obelisk is just as fucked up and terrifying to them as the rest of existence currently is.