During Book 2 Jack assumes that he would not be a target of one of the Ruggie-induced “accidents” plaguing the school, but after Jack confronts Ruggie and Leona about their plans to sabotage the upcoming Spelldrive game Ruggie asks Leona if he ought to “take care of” Jack. Leona does not allow it.
It is Jack who reveals Ruggie’s participation in the incidents of Book 2, and it is possible that he saved Ruggie’s life by turning into his wolf form to distract Leona long enough for Riddle to intervene when Leona first invokes his unique magic.
Jack turns into his wolf form in both Book 7 and during Vargas Camp for the purpose of carrying Ruggie, but Ruggie is quick to leave Jack to his own devices during the drama of Tsumsted.
When Ruggie and Leona overhear their fellow dormmates plotting to “knock Jack down a peg” out of jealousy over his athletic talents, Ruggie tells Leona, “It probably wouldn’t hurt to let ‘em put a little fear into Jack and teach him to respect the rest of his dorm”. Leona decides to protect Jack anyway, with Ruggie having to intervene to keep him from using his unique magic on the bullies.
When Jack thanks Leona for the help Ruggie responds, “You’re taking this like a man. I was expecting more lip from you.”