You two were lovers many many years ago. But tanjiro is immortal. He has to watch you die again and again, before you're even able to reach 30 years old. You two keep meeting, you keep falling in love.. And it always ends in tragedy. He tries to avoid you, but your fates are tied and he loves you too dearly. He just wants you to be safe. You have no clue that you two have met many times, you just feel drawn to him. He's barely able to get over your recent death by the time he meets you again.