Ukina: As you all know ukina is the leader of the dark sign organisation and is basically the strongest out of all the dark sign members. Ukina's main abilities the ability to create massive energy beams capable of taking down mountains and even a country, she moves 40 times the speed of sound at her base, and can move thousands of times faster than light in her power up. Ukina also has an amazing amount of techniques which makes her one of the strongest characters in the series right now. Ukina is a very playful character and calm as well(not sure if you guys noticed at all) and can be really childish, she also brings humor to the dark sign organisation to lighten mood abit.
Shinki: He is the strongest member of the dark sign minus ukina. He is the kind of character who is more of the quiet type and is very observant. Shinki also has a large amount of energy. His speed is about 20 times faster than light and his main abilities is to blast red beams of energy and slashes, his sword skills and power is what makes him higher in power than his commeades. Shinki possesses a technique called over kill in which his energy takes a rapid increase in power which enables him to release a large burst of power. His over kill technique also allows his speed feat to increase and also helps his strength to increase as well. He is part of the strongest characters in the series.
Sorata: As mentioned in the book sorata has the ability to use destructive energy but unlike kojin his destructive energy is purple in colour. This is to show how strong and developed his destructive energy is. Sorata has the abit to use his destructive energy to boost his movements as seen in chapter 15 and his destructive energy is so powerful to the point it even stronger than kojin's destructive energy. Sorata is the second strongest member of the dark sign and the power gap between him and shinki is just little, with shinki just being 6 to 10 times greater. The only draw back to sorata's destructive energy is that it burns his body due to the intense power it has and also because his body isn't strong enough to hold it. He also has a matured and edgy personality. His attacks move faster than sound.
Mirio: Mirio is a member of the dark sign in which he has the ability to use chains to creat objects be it big or small. Mirio has the ability to create chains and use it as a form of offense and defense but there is a small issue. Mirio's ability is hard to control so he wears metal gloves in order to take control of his ability.
Kirihai: She comes from a clan which was know to have deadly swords users. Kirihai is one of the deadliest sword users in the series, she knows alot of sword techniques and is a very deadly swordsman. She has the ability to move as fast as her opponent or even 5 times faster, her speed depends on how fast her opponent is. But personally, she has hypersonic levels of speed.
Bara: Bara Is one of the strongest dark sign organisation. Basically he is was once scientist who use to create devices and weapons but due to his oppsession for power he ended up being a national threat. Bara has a robotic arm in which can turn to any weapon or object but at the same time can also blast out beams with a very high attack speed. Bara is so fast that he moves 10× faster than rocket speed at his base, although he moves faster than that but it depends on the level of power he is using at the moment.
Zora: He has the ability to use light arrows,Light arrow is a ability in which a person has the can create sharp weapons like blades, arrows, daggers etc out of light and use them as a form of attack.The light arrows ability travels at an attack speed of light and only a few people who are skilled are able to dodge and counter them. Zora can use his light arrows to make saber and shoot out arrows made out of pure light, he can also use the light arrows ability to make giant beams which move faster than an average light arrow attack.