No specific information given out by CLAMP.

<Asuka> He's cute!  I want him!
<ChunHyang> You?  Miss "he's too short"?  Want
            Ascot?
<Asuka> He's SO short that he's
        cute!
<Satsuki> I don't think he would give up on Umi
          easily.
<Alice> What was he?
<Rei> Bal / Shoukanshi (Summoner).
<Yang> Summoning?  That sounds useful...
<Shinji> And a couple of the summoned monsters were
         pretty small and cute....
<Satsuki> Doesn't seem to have a particular element.  
<Alice> Could be earth, because creatures roam the
        earth. 
<Asuka> Why was such a cute boy working for Zagato?
<Satsuki> Zagato promised a haven for his "friends"
          (the creatures he summons).  Supposedly
          he's seen a lot of hardship coming from
          hardheaded, old-fashioned Cephirans that
          thought that the creatures were monsters and
          therefore harmful.... who never listened to
          Ascot's pleas that his friends were
          completely harmless.... so he had no place
          where he could live happily with his
          creatures when Zagato came up with his offer.
<Shinji> How sad....
<Alice> In the end, he lives happily with the rest of
        the RE1 crew in the central castle of Cephiro.
<Rei> There, he learns spells from Clef.... he used
      one in the RE2 manga.
<ChunHyang> He used it to save Umi.
<Asuka> You would think Umi would be less dunce about
        her own suitors..... I mean, Clef and Ascot
        show at least SOME interest in her, and
        well, she's not hooked up with either by
        the end!!
<Alice> Wouldn't that be a spoiler comment?
<Satsuki> I think it's not a plot spoiler or an
          identity spoiler so we can let it go. ^_^
<Suu> He didn't show signs like that in the OVA....
<Asuka> GODDAMMIT why is he still short in the OVAs!?
<ChunHyang> And he was such a PRICK.....