Finally I got Fenrir to stand on his own. Over the last weeks I have been slowly toiling away, painting the legs and pelvis. Due to the amount of customization and my otherwise over complicated paint scheme it has taken much longer than I thought. But it is finally done and I have glued the legs into the feet and Pelvis as well as attached the feet to the base with the screws. Now it is standing solidly. What is left is to fit all the pistons and paint them as well as the cables and then the legs are done, except the armor which I have not finished sculpting (mostly due to lack of inspiration).
Now I just have to sort of the mounting of the weapons (they are not as secure as I had hoped) and the shoulder guards before I finalize the upper body and start painting.