Comfortable: 相手's simply no threat to 自分's life
Resting: 自分 doesn't expend stamina at all
Untouchable: 相手 cant touch even a strand of his hair
Security: His sword destroys all threats passively
Never Vulnerable: He attacks/defends even when unconscious
Stuck in endless war in a world where death's not permanent, 自分's sole comfort was his sword
There it is, cold steel resting gently by his side
It was security, his peace & rest
For no being, not even 相手, can reach 自分 as long as he has his companion, rendering him unassailable
So ultimately, there's just no meaningful way to physically reach 自分, so he shall remain in peace, & have his way.