This must surely be I, Weapon, a novel by Charles W. Runyon, first published in 1974.

The humans had been heavily defeated in a war against a race of marsupial aliens called the Vim. The remaining pockets of human civilation lay on the moons of Jupiter:

The sole exception was the Jovian moon-people. At the time of the Vim disaster they numbered only about thirty thousand scientists and their retainers scattered over the moons of Ganymede, Callisto, lo, and Europa. They grew their own food in hydroponic tanks, mined the minerals needed to synthesize their own air and water — in short, were self-sufficient, intelligent, and highly adaptive.

They formed a society called the "Jovian Lunar Confederacy", which became abbreviated to "Jelk". As the OP recalls, these survivors modified themselves genetically to be short and hairless:

Jelks averaged four feet in height, with small bones, delicate features, and unusually large eyes, due to the fact that heights were kept dim in the Ganymede caverns in order to conserve energy. They were hairless as eggs, an evolutionary development which also took place in the underground culture, with its emphasis on purity of air and cleanliness of body.

They began a breeding program to create a supersoldier to defeat the Vim, and eventually bred a man named "Raki" (rather than "Kofi") who met the requirements.

The full story is available from the Internet Archive.

This must surely be I, Weapon, a novel by Charles W. Runyon, first published in 1974.

The humans had been heavily defeated in a war against a race of marsupial aliens called the Vim. The remaining pockets of human civilation lay on the moons of Jupiter:

The sole exception was the Jovian moon-people. At the time of the Vim disaster they numbered only about thirty thousand scientists and their retainers scattered over the moons of Ganymede, Callisto, lo, and Europa. They grew their own food in hydroponic tanks, mined the minerals needed to synthesize their own air and water — in short, were self-sufficient, intelligent, and highly adaptive.

They formed a society called the "Jovian Lunar Confederacy", which became abbreviated to "Jelk". As the OP recalls, these survivors modified themselves genetically to be short and hairless:

Jelks averaged four feet in height, with small bones, delicate features, and unusually large eyes, due to the fact that lights were kept dim in the Ganymede caverns in order to conserve energy. They were hairless as eggs, an evolutionary development which also took place in the underground culture, with its emphasis on purity of air and cleanliness of body.

They began a breeding program to create a supersoldier to defeat the Vim, and eventually bred a man named "Raki" (rather than "Kofi") who met the requirements.

The full story is available from the Internet Archive.

This must surely be I, Weapon, a novel by Charles W. Runyon, first published in 1974.

The humans had been heavily defeated in a war against a race of marsupial aliens called the Vim. The remaining pockets of human civilation lay on the moons of Jupiter:

The sole exception was the Jovian moon-people. At the time of the Vim disaster they numbered only about thirty thousand scientists and their retainers scattered over the moons of Ganymede, Callisto, lo, and Europa. They grew their own food in hydroponic tanks, mined the minerals needed to synthesize their own air and water — in short, were self-sufficient, intelligent, and highly adaptive.

They formed an organization called the "Jovian Lunar Confederacy", which became abbreviated to "Jelk". As the OP said, they began a breeding program to create a supersoldier to defeat the Vim, and eventually bred a man named "Raki" (rather than "Kofi").

The full story is available from the Internet Archive.

This must surely be I, Weapon, a novel by Charles W. Runyon, first published in 1974.

The humans had been heavily defeated in a war against a race of marsupial aliens called the Vim. The remaining pockets of human civilation lay on the moons of Jupiter:

The sole exception was the Jovian moon-people. At the time of the Vim disaster they numbered only about thirty thousand scientists and their retainers scattered over the moons of Ganymede, Callisto, lo, and Europa. They grew their own food in hydroponic tanks, mined the minerals needed to synthesize their own air and water — in short, were self-sufficient, intelligent, and highly adaptive.

They formed a society called the "Jovian Lunar Confederacy", which became abbreviated to "Jelk". As the OP recalls, these survivors modified themselves genetically to be short and hairless:

Jelks averaged four feet in height, with small bones, delicate features, and unusually large eyes, due to the fact that heights were kept dim in the Ganymede caverns in order to conserve energy. They were hairless as eggs, an evolutionary development which also took place in the underground culture, with its emphasis on purity of air and cleanliness of body.

They began a breeding program to create a supersoldier to defeat the Vim, and eventually bred a man named "Raki" (rather than "Kofi") who met the requirements.

The full story is available from the Internet Archive.