Deesum was a member of the Wandering Noonvale Companions Troupe. Deesum was fiercely defensive of her nephew Dwopple, always coming to his defense even if, as was often the case, the mischief going on was Dwopple's fault--other beasts would accuse her of spoiling him and being far too soft with him, but she would attest that she loved him "like a mother." This habit, as well as her generally stubborn demeanor, often brought her to odds with Florian. She came to Redwall with the rest of the Troupe after their cart became mired in Mossflower during a heavy thunderstorm.
Deesum was a bit was prone to speaking in a very flowery manner and reacting quite overdramatically to a situation--when Janglur informed the Troupe that they would have disappeared in a swamp had the cart gone much farther, she performed a graceful faint. A sharp nip in the tail from Ellayo soon brought her around, however. She was gravely concerned when Dwopple was kidnapped by the Marlfoxes, although she still refused to discipline him when he was returned safely.