After seeing a flashback of Sebek and Silver together as children Grim says that they haven’t changed a bit since they were kids but Sebek insists, “Don’t compare me with Silver! I’ve grown plenty more than he has.”
When Lilia tells Sebek not to rescue a baby bat from a tree because if it falls and gets hurt it can just heal up again Seek reflects, “Silver…for the first time in my life, I think I respect you.”
During Book 7 Sebek says that Silver has easily faced foes many times worse than the darkness and he will be perfectly fine.
Sebek will often be strict with Silver, telling him that he had better not do anything that would reflect poorly on Malleus and Lilia during Fairy Gala, and occasionally Silver will return this energy in kind, reprimanding Sebek for not being ready to act when he is truly needed if he gives in to paranoia and giving him orders during Book 7.
It is occasionally hinted throughout the game that Silver is actually the stronger of the two apprentice-guards. Silver calls Sebek out on his slow footwork during Glorious Masquerade and Sebek loses a mock-battle they have in the school courtyard, with Sebek assuring Silver than one day his progress will soon outpace Silver’s own.
Sebek also fights Silver and loses when trying to protect Malleus at the beginning of Book 7, and we see a flashback of mock-battles between the two when they were children, when Sebek would lose to Silver.
Sebek admits that he has only ever beaten Silver a handful of times.
In another flashback we see a young Silver using magic before Sebek, and when Sebek attacks Silver in earnest in an attempt to save him from his own despair, he loses again. Silver suspects that Sebek actually lost the fight on purpose in a bid to save him but Sebek retorts with, “I fought with all I had! But I couldn’t win, confound it! Do you know how frustrating that is?!”
Twisted Wonderland Reference Note 