Complex sentence: He finds King personally engaging and he desires or needs whatever small survival advantages King can provide, but Marlowe comes from the same social, economic and military background as Grey, and understands and somewhat sympathizes with Grey's insistence on discipline and strict adherence to rules.
Split into simpler sentences: He finds King personally engaging and he desires or needs whatever small survival advantages King can provide. Yet, he understands and somewhat sympathizes with Grey's insistence on discipline and strict adherence to rules.