Mahou? Sonna Koto yori Kinniku da!

Alternate Name: 
Magic? Muscle is Stronger! ; 魔法?そんなことより筋肉だ!
Japanese Manga (Read from left to right.)

Mahou? Sonna Koto yori Kinniku da! summary:
There was a youth who lived deep inside a Forest, his name was Yuri.
After he trained his body for long, he achieved a special trait which made his body able to withstand almost every kind of magic.
One day, there was a beautiful elf named Firia, who got lost and arrived at his house.
Yuri, who was attracted to see the world, together with Firia, they set out on a journey around the world.
“Yuri-san, can you use magic?”
“Of course I can. It’s called muscle magic.”
“…what, is that?”
“In exchange of magical energy, I use my muscles to emit a powerful magic.”
“That isn’t magic but simply a feat of strength.”
This is the tale of a youth who chose to polish his muscles and journey around the world together with a peerless beautiful elf.