I notice my mage, with LV23 is with HP19 and 1 of endurance! This is normal? Or a bug? Just now I notice that, or is a curse? Or is this one penality for I came to the volcano cave early?

Have you checked the character's age? One of the most obvious reasons for the low status could be that he's been excessively aged (resulting from certain monster attacks). If so, you'll need to complete the 4 seasons quest line to obtain a method of restoring his natural age.

I make this, but hi's a elf, and now have 31 years old :\

Certain things will permanently reduce a character's endurance. The raise dead spell, I think, will resurrect characters but they will lose a point of endurance each time. Taking a character to the Temple and paying for resurrection will not incur this penalty. There may be other spells that can reduce endurance, and even some monsters that can cause it.

If it's some kind of curse or temporary condition, you can try visiting a Temple to see if they can heal it. If it's permanent, then I think there are fountains in the world that can boost your endurance back up. Others in these forums are experts and know the locations of all of the stat boosts and can help you out.

In one of the cult dungeons in Clouds, there is a fountain that will permanently increase Endurance as long as it's below a certain value; that can be used to fix characters whose Endurance has permanently dropped too low. This should help, provided the character isn't excessively old (where "excessively", I believe, means triple digit age).