This is Doomsday from the "DC Collectibles The Death of Superman Doomsday & Superman Deluxe Action Figure (2 pack)"
This is one of the best Doomsday figures I’ve seen –aside from the horrible lack of articulation in the arm. The forearms barely move inward at the elbow joint. My “Before” picture shows how far the arms will move in. I was reluctant to carve into a figure I spent over $70 to get (-it does include superman). Nevertheless, I’m glad I took my trusty dremel to it. Look at the vast improvement in the “after” picture.
The last two photos show how much I took away. I boiled and removed the forearm, then scraped away the inner arm at the bicep.
After this very slight modification, I don’t think it looks bad when the arms are straightened. The exchange for having a little gap at the crook of the arm is well worth now being able to bend the arms in. It’s not quite 90 degrees, but good enough.