Aside from Zabimaru, Which Zanpakuto do you think didn't reveal its true name to its User when he/she achived "Bankai"?

Basically, the title

Apparently, Zabimaru didn't respect Renji enough to gave him its true name, and its full power. Until later in TYBW arc, where Renji is now seen as deserving of Zabimaru's power.

Now, aside from Zabimaru, which other Zanpakuto do you think didn't reveal its true name yet?

My Guess would be:

Zaraki's Zanpakuto. It is called "Unnamed" for now. I think it has a real name.

What do you think?

Basically, the title

Apparently, Zabimaru didn't respect Renji enough to gave him its true name, and its full power. Until later in TYBW arc, where Renji is now seen as deserving of Zabimaru's power.

Now, aside from Zabimaru, which other Zanpakuto do you think didn't reveal its true name yet?

My Guess would be:

Zaraki's Zanpakuto. It is called "Unnamed" for now. I think it has a real name.

What do you think?