Two of my favorite series' are Harry Potter and Keeper of the Lost Cities. Here are some similarities between some of their characters!
1) Councilor Bronte and Severus Snape : Both of them didn't like the hero/heroine at first (in this case Sophie and Harry) but later on helped them. Both of them seemed to be bad characters but then turned out to be one of the best.
2) Grady Ruewen and Arthur Weasley : Both of them are father-figures to Sophie and Harry respectively. They both help the main characters or each series achieve their goal.
3) Edaline Ruewen and Molly Weasley : Just like Grady and Arthur, Edaline and Molly are mother-like figures to Harry and Sophie.. Both of them look like they are harmless but can cause some real trouble when needed. Both of them are extremely fond and protective of Sophie and Harry respectively.
4) Stina Destry Heks and Draco Malfoy : Both of them looked down on Sophie and Harry (respectively) at first, believing them to be 'inferior' and 'low down'. As the series' progressed, both of them turned good and helped the main characters with their mission. Even though they proved themselves loyal to the good at the end, Sophie and Harry still consider them jerks.
5) Mr. Forkle and Albus Dumbledore : Both of them are powerhouses of information for Sophie and Harry. Both of them died tragic deaths at the hands of the villains and withheld crucial information from the... at the risk of being repetitive, main characters.
6)Lord Cassius Sencen and Lucius Malfoy : They are both fathers, they both look bad, they both love their sons, they both expect the best from their sons, working them too hard. (Although one of them bred a prankster and the other a muddled youth - quite different things)
7) Sir Tiergan (Granite) and Professor McGonagall : They are both teachers who may have shown some partiality to Sophie and Harry (shh! don't tell them that). They both are strict and teach really well and can be trusted to give wise advice.
Councilor Kenric and Sirius Black : They were both close to Sophie and Harry and the both died tragic deaths. Both of them were like fathers to the main characters and departed far to early.
That's it for this post. Let me know which two books I should combine next!