Boy Name Ender
Male Name Ender, Kun
Add this to the end of someone's name, it's like saying ______buddy. It's generally used as a name ender (like さん) for boys and young men. Don't use this on people who are higher ranked than you (socially or literally). As in, you wouldn't use it on your boss. Use it on your younger male subordinates as well as boys who aren't adults yet.
くん
The reading is the same as the one you learned with the kanji (on'yomi), probably because it usually is attached to other words (aka names, like こういち君) making it act more like jukugo words do.
今年の夏、私は山田君と、ディズニーランドの中にあるホテルにとまりました。
This summer, I stayed in a hotel in Disney Land with Yamada.
ビエト君って、せんたくきを一日に七十七回も回すらしいよ！
I heard that Viet runs the laundry machine seventy-seven times a day.
日本の男の子の名前の後ろには「君」という言葉が付けられるそうだが、ラという名前の男の子があまりいないというのは残念ですね。
"Kun" is used as a suffix for boys’ names in Japan. It’s too bad there aren’t a lot of kids with the name "Ra."