Ronin, who had been hiding in Albestros's shadow all this time finally showed up as soon as the old man's life was at stake.
Kahn who always thought of a backup plan when it came to doing something or keeping an eye on someone, had ordered Ronin to safeguard the old man by hiding in shadow in case he wasn't around.
Albestros had a very important part to play in their business enterprise and in a way, he was the surface owner. It was his name and skills they'd need to use in order to run their shop. So no way Kahn wouldn't take measures to safeguard the old grandmaster blacksmith.
He didn't trust any of the external help and they were all part of the security on the name only. The real security was Ronin who also had the ability to perfectly merge inside a shadow.
And ever since Kahn unlocked the Impartation Skill after Omega & Six Generals were revived, Ronin had received all Kahn's Assassin skills including the merged abilities he created.