Why didn't Orochimaru fight Madara in 4th Great Ninja War? I think Orochimaru was strong, like the other Kage, if not stronger.
There are two reasons: 1)Orochimaru was busy reanimating the four dead hokages to bring strong reinforcements. 2)Even if he was as strong as the Kages or even stronger, but we see in the fight between Madara and the Kages just how strong Madara was. He singlehandedly annhilated all the five Kages. So if Orochimaru decided to face him alone then I am sure he would have died instantly.