i think danzo would win beacuse of KA, but if obito phases into the ground the attacks danzo from belo he might gat a chance to kill him. obito is most likely going to charge at danzo while intangible like he usually does but assuming he decides to teleport behind danzo he could then warp away his head or stick his intangible hand into his brain/heart and make it tangible. the only problem obito might have is the izangi(which danzo can use 10 times) but if he kills danzo fast enough then it shoudn't be a probem
under normal circumstances ninja don't start with their ultimate techs so danzo wont start with KA and obito probably wont teleport behind danzo at the begining of the fight. but danzo wins this 7/10 times
danzo low diff (if he starts with KA)
obito low mid diff (if he teleports behind danzo and does what i stated above)