>>96719850
Relations with the Imperium are tense but mostly friendly. Sort of. The Imperium would like to absorb them into the fold, as they are a staunchly anti-chaos faction. Unfortunately, experiences with Chaos Marines has left Space Bretonnia with a distaste for Marines in general. They keep the Imperium at arm's length, but there is a nominal peace on paper. In practice, individual elements of either faction frequently squabble over border planets. If Space Bretonnia was weak enough, the Imperium would probably just dispatch an army to conquer and integrate them, but that has proven impossible under the current circumstances. They can't spare the forces from external threats, the Bretonnians are at least humans (even if they don't really care for the Emperor) and they hate Chaos with a passion, and they're too big to conquer quickly if a force could be spared to do so. It would leave the Imperium too vulnerable, be too costly, and overall accomplish very little of worth. The fact that they treat diplomatically with Xenos is a concern, but the knights don't seem to be directly under Xeno sway.
Space Bretonnia is willing to let the Imperium consider them a disposable buffer state, at least for the time being.
Eldar see them in much the same light as any other humans, though Eldar who bother to study aliens have noted the odd similarity to their own culture in places.
Space Bretonnian upper echelons are aware of Lileath and her priestesses and are aware they are in hiding. They try to remain cordial with the Eldar, but for obvious reasons conflict remains commonplace.
Tau hardly see them as any more than an unusually large human rump state. Diplomacy has been successful, but proselytizing has been largely fruitless.
For the frenchies, the Tau are seen as a potentially useful ally but their religion is meaningless. They already have the Maiden, thank you.
They trade with the Squats.
Orks/Deldar/Nids/Etc are all seen as foes to be vanquished and nothing more.