慎剛: a male given name

信号: signal

龍臣: a male given name

神髄, 真髄: (figurative): The spirit or soul of something: its essence, its true quality. / 心髄: The marrow or core of something. / 神瑞: A good omen.

神秘: mysterious

神秘: mystery / 真皮: dermis / 真否: true or false / 心皮: carpel

鍛冶神: (mythology, Shinto) the Japanese god of the forge, metalcraft, and blacksmithing

gods; deities; divinities; spirits. / mind; psyche; spirit; soul.

新書: new book / 信書: letter / 真書: square style / 親書: handwritten letter / 心緒: emotion / 親署: signature from the emperor / 参薯, シンショ: water yam

親署: for the emperor to sign