Wairua means sipirt in Maori, the spirit within.
The spirit is being depicted as a taniwha, a feared dragon like beast. The taniwha in this image is based on the New Zealand native reptile, the tuatara.
The tatoos are a Ta Moko, moari tattoo, the same tattoo design that 'tribal' style tattoos are based on.
I used these images by Vishstudio as reference:[link][link]