The Scepter

I’ll leave aside the fact that Thor, at the end of the Avengers, didn’t take the Scepter with him – even though it was a very powerful weapon. The fact that it had an Infinity Stone etched in it is what bothers me. We do know that Thanos gave the Scepter to Loki. But we also know that Thanos is after the Infinity Stones. So why did he give one to Loki?
I understand why this twist was necessary. However, it just doesn’t work. The Mad Titan must be truly mad in order to give such a powerful artifact away, even if the outcome could be that he gains an additional one.
Of course, it can be said that Thanos was just testing the strength of Earth’s heroes. But, in doing so, he helped in the creation of the most powerful Avengers (Scarlet Witch and Vision). Maybe we will find out why he did this later on, as the story unfolds.
But I doubt it will be so.
