but how can you get ending pregnat by L ? creampie before fighting boss ?
Not quite. There's a bit of a gimmick to it, but, it's been
quite a while since I fully played this game, so take this info with a grain of salt, since I might not remember everything correctly.
The game essentially simulates something like a cycle for Kana, and as such, she has days when she's fertile and days when she's not. I don't remember exactly how it works, but I think there was a way to tell on the Status 5 page. When Kana's fertile, creampies have a chance of fertilizing her. Obviously, L has a higher chance than MC to get her pregnant.
Status 5 shows you if Kana's fertilized, but doesn't tell you who did it.
All that means is that if you want Kana to be pregnant in an ending, you need to ensure that L creampies her on days when she's fertile, pass to the next day and see if she was fertilized. If this happened, congrats, you can see the ending variations where Kana was impregnated by L. Where it matters anyway.
The same applies to the MC if you want Kana to be pregnant with his kid.
I don't know if Kana can be impregnated by the bar gang-bang events, or what that does to the endings where the father is acknowledged. Getting her pregnant with
those would be
extremely difficult tbh. Probably impossible without cheating or ridiculous luck... Again, assuming it's even possible.
It's too bad that Kana doesn't care who got her pregnant in the NTR ending tbh. Seems like a wasted opportunity to twist the knife if it was somehow MC's kid.