// Doesn't include Polyphemus (only appears in the Shoals), Murray (Hell),
// or Tiamat (Zot).
static monster_type _choose_unique_by_depth(int step)
{
    int ret;
    switch (step)
    {
    case 0: // depth <= 3
        ret = random_choose(MONS_TERENCE, MONS_JESSICA, MONS_IJYB,
                            MONS_SIGMUND, -1);
        break;
    case 1: // depth <= 7
        ret = random_choose(MONS_IJYB, MONS_SIGMUND, MONS_BLORK_THE_ORC,
                            MONS_EDMUND, -1);
        break;
    case 2: // depth <= 9
        ret = random_choose(MONS_BLORK_THE_ORC, MONS_EDMUND, MONS_PSYCHE,
                            MONS_EROLCHA, -1);
        break;
    case 3: // depth <= 13
        ret = random_choose(MONS_PSYCHE, MONS_EROLCHA, MONS_DONALD, MONS_URUG,
                            MONS_MICHAEL, -1);
        break;
    case 4: // depth <= 16
        ret = random_choose(MONS_URUG, MONS_MICHAEL, MONS_JOSEPH, MONS_SNORG,
                            MONS_ERICA, MONS_JOSEPHINE, MONS_HAROLD,
                            MONS_NORBERT, MONS_JOZEF, -1);
        break;
    case 5: // depth <= 19
        ret = random_choose(MONS_SNORG, MONS_ERICA, MONS_JOSEPHINE,
                            MONS_HAROLD, MONS_NORBERT, MONS_JOZEF, MONS_AGNES,
                            MONS_MAUD, MONS_LOUISE, MONS_FRANCIS, MONS_FRANCES,
                            -1);
        break;
    case 6: // depth > 19
    default:
        ret = random_choose(MONS_LOUISE, MONS_FRANCIS, MONS_FRANCES,
                            MONS_RUPERT, MONS_WAYNE, MONS_DUANE, MONS_XTAHUA,
                            MONS_NORRIS, MONS_FREDERICK, MONS_MARGERY,
                            MONS_BORIS, -1);
    }
    return static_cast<monster_type>(ret);
}

    // Doesn't include Polyphemus who only appears in the Shoals.

    // First, pick generic unique depending on depth.

        ((lev > 19) ? random_range(MONS_LOUISE, MONS_BORIS) :
         (lev > 16) ? random_range(MONS_ERICA, MONS_FRANCES) :
         (lev > 13) ? random_range(MONS_URUG, MONS_JOZEF) :
         (lev >  9) ? random_range(MONS_PSYCHE, MONS_MICHAEL) :
         (lev >  7) ? random_range(MONS_BLORK_THE_ORC, MONS_EROLCHA) :
         (lev >  3) ? random_range(MONS_IJYB, MONS_EDMUND) :
                      random_range(MONS_TERENCE, MONS_SIGMUND));

        ((lev <=  3) ? _choose_unique_by_depth(0) :
         (lev <=  7) ? _choose_unique_by_depth(1) :
         (lev <=  9) ? _choose_unique_by_depth(2) :
         (lev <= 13) ? _choose_unique_by_depth(3) :
         (lev <= 16) ? _choose_unique_by_depth(4) :
         (lev <= 19) ? _choose_unique_by_depth(5) :
                       _choose_unique_by_depth(6));

    // If applicable, replace it with one of the uniques appearing
    // only in some branches.

        // Usually, we'll have quit after a few tries. Make sure we don't
        // create unique[-1] by accident.

        // Usually, we'll have quit after a few tries. Make sure we have
        // a valid unique.