idiom about two dominant persons and high profile people

[Koalachan]

Hi

I am wondering whether there is an english saying for the following:

1. It's about you cannot have two dominant persons in a given space or department as they tend to argue or fight

2. High profile people (eg politicians) are very likely to get attacked (so it's important to be humble)

Please let me know if there are any saying or idioms for the above.

Many thanks in advance. Much appreciated!

[Pasban110]

Hi.
For the first part, I think it is: One master in a house is enough .

[Pasban110]

And for the second one, what about: A wolf in sheep's clothing. It is not that proper, is it?

[Koalachan]

hi thanks pasban110....i like the first one! the second suggestion is more like having hidden malicious intent, isnt it?