She apparently has control over the Reaper Mats as she ordered them to take Vice Principal Victoria away to Coral Grove after her failure. She then undid the hypnotism that was affecting nearly every student at the dance but removed any memory they had of being hypnotised, ensuring The Council's existence remained a secret. The Outcasts were not cured of their 'curses', however.
She also appears in the intro for season 3 episodes.
She is not above threatening people to get her way as seen in Fight or Flight.
She taught and fought evenly with The Serpent, meaning she is most likely a black belt in martial arts.
The reason she owns MWF might be because Elizabeth Mann was Cassandra's great grandmother.
She made her money as a powerful and ruthless boss of Mann, Wurst and Finnwich now that she is very rich and lives with her only daughter Kimmie in a big mansion equipped with security cameras, kitchens and other modern furniture and grandeur. She also has a secret room where she does her secret spy work for world domination. She is extremely harsh and is also in charge of who gets shipped off to Coral Grove. Given her high position, she controls the stock market with her investments and the politicians with threats and the only thing she can't control is Lee Ping.
Cassandra is head of the Council. This seems to place in in charge of several big cooperate businesses including Mann, Wurst and Finnwich and all reaper-Mats. She has also claimed to have hold of politicians in Fight or Flight.
In Band of Heroes, Cassandra demonstrates impressive fighting abilities and even revealed she has trained the Serpent. Though her fighting was mostly done while she was operating a mechanical suit that grants her flight and beams like the reaper-mats.
She even revealed to Biffy in the episode "Band of Heroes" that she is EVIL. For a second, in Date With Destiny, it seemed like she was helping Lee and his friends, and then when asked possn's" technology to get richer, at which point Kimmie Mann crystalized her.