The first Singapore Shield defied the marauding bands of Japanese soldiers during World War II. He wasn't able to defend Singapore, but managed to hold the ground while many people, especially foreigners, evacuated in planes. He was captured by the Japanese, but managed to escape within a month and led a band of locals in a guerrilla war against the occupied city. The second Singapore Shield was active in the 1970s and briefly joined a United Nations sponsored team, Pacifica, but after it folded due to internal differences, Singapore Shield returned to his city and became its champion.

When Evol Khan took the presidency in 1986, Mah Boon Kiang's grandfather was the third Shield. Khan met with Kiang and threatened him, suggesting that if he continued to act as the city's champion he would find his family would begin to disappear. Kiang reluctantly retreated from public life. When Mah Boon was born, the Kiang family saw in him the opportunity for the tradition to be carried on. He grew up under the watchful eyes of his grandfather and learned Kung Fu firstly with his grandfather, and later with a Master in Vietnam.

Atomic Girl had become the living legend of Singapore, and had established a group of heroes to help her keep order in the city. When Mah Boon returned to Singapore in 2004 he attended a team try-out and was able to defeat all the contestants and gain a place with the Singapore Samurai.

He believes in the traditions of Singapore and considers Evol Khan as a travesty against this history. His grandfather has counselled him to be patient, but Mah Boon feels that he is capable of facing off against Khan and is just waiting for the right time.

Mah Boon is idealistic and infused with the pride of his family tradition. He is only a teenager, and although he has captured the adoration of Singaporeans, he is also seen as young and inexperienced. This is not entirely true, as he has developed quite a maturity through his martial arts training and is capable of facing off against even the most hardened of criminals, including the terrorist group Marauding Tide.

“I'd be happy to put you on the ground, old man.”

Singapore Shield has historically relied on a combination of martial arts training and the use of an almost indestructible shield. The original shield was lost in World War II, but a replacement was forged in the 1950s and has been handed down to each new generation. Mah Boon has proven adept at using the shield in a variety of ways including as a deflector against almost all attacks, and an extra weight in clobbering opponents.

Mah Boon is a young and highly trained martial artist, having been trained since the day he could first walk. He is lithe but powerful, and wears loose-fitting black pants and tight gloves, preferring to appear bare-chested as the previous Shields had done. The Shield is red and white in the colours of Singapore, and is composed of an unusual blend of tough metals, although the exact makeup is unknown.