Towerfolk: Retaliation

Biggy the Giant has been coming to earth since 200? to slay Monsters and protect humans. Despite his success at slaying the invading monsters, millions of people have been killed.
The United Nations have created a group called Obelisk, whose job it is to collect and study all material relating to Giants and Monsters, including body parts. 
The other task of the group is to create devices, tools and plans to combat the Monsters, and if necessary, the Giants. One such plan has been created by a scientist Arthur Harland, called Project Walking Wall. This project centers around using Giant DNA and injecting it into human test subjects to create Human-Giant Hybrids. A breakthrough has occurred and scientists have developed a special pill which when ingested allows the consumer to turn into a giant version of them selves. The transformation takes 1 minute and lasts several hours, at which point the subjects return to their normal sizes. They currently have 12 hybrid soldiers and have built customized giant uniforms and weapons for them to use. If the hybrid loses consciousness, they will return to their normal human size. 
One such soldier, an American named Trevor Vanton, harbors a deep hatred towards the Giants and Monsters. 
The soldiers and their equipment have yet to be used against an actual Monster due to their slow response times which is a result of the randomness of the appearances. 
Unbeknownst to the humans, the giants have been monitoring the hybrids from their own world. This is possible due to the hybrids being part of Biggy, due to his blood being used to create them.
An opening Gate is detected in North America and the closest Hybrids are called forth. They ingest their serums and put on their gear. They arrive just as the Monster begins to wreak havoc. They are not use to their precise situation and as a result while the group are successful in slaying the monster, it takes them longer than expected, they cause a lot of damage and they themselves suffer injuries.
As they gather themselves upon a job well done, Biggy appears. They Giant slowly approaches the Hybrids and the dead monster. The hybrids are on their guard. Biggy approaches the corpse and they allow him to splash the creature with the Ash Water. When the creature doesn't disintegrate he decapitates in. Only then does the monster turn in ash with the special water. Following this the Hybrid Owens stares intensely at Biggy, who is unaware that Owens lost his family because of the monsters and Biggy back in 200?.
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Biggy is administered first aid and an enclosure is placed around him and guards are put in place. Owens takes the opportunity to gloat and sing his own praises, but feels Biggy should just be killed.
The public is divided on what to do with Biggy. Some say he should be released, while others say he should remain in custody, for various reasons.
The opportunity to question and interview Biggy is jumped upon. It is noted that Biggy seems to understand the English language but does not answer.
In Biggy's home world, several huge sand timers are counting down. One finishes and an elderly Giant calls for someone. A Chinese-style dressed Giant appears with a large box strapped to his back.
Back on Earth, without warning, the Box Giant appears and makes his way towards Biggy, arriving there in no time. The Giant, Chains, is able to break through the human defences quite easily and is able to release Biggy, but he is confronted by the Hybrids. Despite having guns and missiles, Chain manages to avoid any serious damage and instead uses his chain box to devastating effect. Additional military forces provide no real help. Owens continues to fight but he fares poorly against Chains and ends up being suspended in the air by his neck, where a revived Biggy stabs him repeatedly, killing him. Chains and Biggy then leave through a portal.
Back in their own world, Biggy and Chains are greeted by the old Giant.
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Biggy, brandishing new weapons, armour and clothes appears in North America.