The mobile ports of Madou Monogatari were really done by Sega, but all of them are licensed from another company.
Looks like that Compile Heart still holding most of the IPs from the already dead legendary game company, Compile.
Compile Heart also made an announcement recently saying they are working on new games for the most famous IPs from the dead Compile.
They can use Madou Monogatari world if they want, but not the characters, which Sega holds the IP. It's the same shitty thing that happens with Guilty Gear series: Sega holds the characters IPs, but not the world.
It's nonsense...