This leader has two things that remind him of his humanity: his shoes, and his hat. These two things remind the leader of his humanity because humans are the only ones who wear shoes and hats.
Another thing that reminds you and the leader about your humanity is wearing jeans (じん). Jeans are the go-to legwear for many people, and no one but humans wear them. Jeans are another great symbol of humanity.
Currently there are no similar looking kanji which exist in the WaniKani learning system