Hi thanks a lot for your comment !
It is indeed a saxophone used on most tracks (from a DecentSamples VST which sounded very nicely, at least for a free VST), I wanted to use it as a warmer texture for the tracks (I listened to the soundtrack from The Odyssey which had nice wind/brass instruments too so I wanted to bring a bit of it into my soundtrack).
And yeah I also wanted the duets to have a different vibe (for the universe they come from but also to bring variations to the pacing of the album), glad that it came accross.
Thanks a lot for listening !