1945. What character can be added to both of these characters to give other characters? ネ_ -> _反

ネ  Katakana "Ne" or The "Shimesuhen" radical - altar, festival, religious service

反  HAN, HON, tane, so(ru) - anti-, bend back

Add 土:ネ+土 土+反  

土  DO, tsuchi - earth, soil

社  SHA, yashiro - shrine, company

坂  HAN, saka - slope, hill