GR translation: improbable as a Zouave

[Mike Jing]

V91.40-92.1, P93.33-35   Out on a little pond the black man is down from
London, ice-skating, improbable as a Zouave, riding his blades tall,
dignified, as if born to them and ice not desert.

What does "improbable as a Zouave" mean here?

Is he really a Zouave? The answer seems to be yes, since later in the book
we find:

The Zouave has gone back to his unit in North Africa, back under the Cross
of Lorraine, . . .