Andre was a Gelumcaedus (an alligator like monster). With his two brothers, he went on mass crime spree breaking into people's houses, while using the sewers as his base. Afterwards he would take his plunder to Florida and enjoy the sun, before hitting another city and carrying on his kinds habits.
At one point Andre along with his brothers, arrived in Portland and carried on there mass crime spree, breaking into people's houses and stealing there belongings.
Either he or one of his brothers murdered a city sewer maintenance worker when he got to close to there lair. The deaths alerted Nick and Hank, who after examining and discovering what they were up against, returned to the sewers to hunt down the Gelumcaedus. Through this Gregorek tried to kill them, but was captured and arrested by the two.
To save his brother Andre kidnapped Hank, and forced Nick to bring Gregorek to him or he would kill Hank. Arriving in there lair, they made the switch, however Gregorek told Andre that Nick was a Grimm, as such they agreed to kill him. Hank managed to warn Nick in time there was a third Gelumcaedus. Nick fought him off, while the other two brothers joined the fray. Armed with his vambrace (an arm protector made by his ancestors to face Gelumcaedus, fitting with a special blade) Nick fought them off, part way through the fight Nick killed Andre, by using the vambrace's blade to slit his throat.