Let's continue and end the list
10. Claudio Serafino
Master of his exorcism sorcery strong enough to match Heihachi his arts can deal serious damage to Devils even as strong as True Devil Kazuya and can fire such powerful attacks like Spear Of Kephalos which i'm pretty sure can take down everyone i placed below him. He can fight close and in distance, he can also trap someone in his chains enough powerful that it takes Kazuya some time to break it so Claudio is incredibly powerful. (he possibly should be higher)
9. Eliza
She's only there because she was supposed to be Claudio rival, Regularly fight with Archers of Sirius even not in her best shape even though her vampire powers are gone she can still release dark waves, fly or trap an opponent and efficiently manipulate her energy as well as heal herself from sleep or drinking blood. I'm pretty sure full awaken Eliza will be stronger than Claudio but unfortunately they made her joke character.
8. Jun Kazama
I may have a bad assumption but it seems to me that Kazama purification powers can suprass Claudio sorcery especially someone as skilled as Jun like she actually boosted Jin to be equal or even slightly above to True Devil Kazuya. Jun also beat Ogre back then. There is not much known about her but from Kazuya's words we can assume that she was pretty strong and it's hard to impress that person. Kazama Essence may be the best counter and one of the strongest power that can match Devil Gene.
7. Kazumi Mishima
Why Kazumi is that high? Because she was sure she can destroy the world with her Devil Gene power. She was also trained by Jinpachi and managed to use some pseudo electric abilities like other Mishimas have and she was also rival to Heihachi she lost to him most likely because she didn't want to kill him and Heihachi is insanely strong so losing with him isn't something you could be ashamed of. She has all powers other Devil Gene users have like shooting lasers using telekinesis or other stuff. So basically she was trained by strongest characters and have strongest power ever existed in the universe.
6. Jinpachi Mishima
Strongest fist the person who trains Heihachi and Kazumi and the original Mishima was trapped by Heihachi because he probably couldn't face him yet. Jinpachi also trains young Kazuya their martial arts which he later developed. upon his return he was possessed by an unknown demon who at that time could only be stopped by Jin in. Main protagonist managed to defeat Jinpachi but he didn't really want to fight him what can we see in his ending where he cries and regrets his actions he performed while he was under demon control. Jinpachi also has some of his demon forms and also can use fire based powers along with his electric Mishima gens even without being possesed. It's unknown how truly strong he was but i feel like every Mishima suprasses him already.
5. Lars Alexandersson
The main protagonist of Tekken 6, the guy defeated literally the entire roster (except for Julia, Lei and Zafina) and faced Jin, Kazuya twice and Heihachi once. Lars also beats Azazel but couldn't kill him because only Devil Gene can do that. Lars has nearly infinite stamina due to traveling all the time fightning dozens of enemies and facing Kazuya, Azazel, Alisa and Jin one after another without getting out of breath. In Tekken 8 he was also able to give good fight to True Devil Kazuya and even give him PTSD of Heihachi. Most similar to Heihachi, Lars also doesn't have Devil Gene and seems to rely more on his electric powers which he can use at such a range that he can even send lightning after his attacks.
4. Heihachi Mishima
Strongest ''normal'' character in this game. No devil powers, magic and other stuff only his Mishimas electric genes. He was always deal with Devil Gene users starting with Kazumi. Heihachi always was equal or maybe even little above to Kazuya since he most likely lost against him in Tekken 1 because of Devil Gene and beat him in Tekken 2 he also makes Jin to use his Devil Gene against him where he beat Kazuya without it in Tekken 4. In Tekken 7 he even managed to face Super Devil Kazuya and knock him out of his form despite being weaker but was ultimately beaten. He came back stronger in Tekken 8 by his traning with Tekken Monks most likely suprassing Lars and capable of casually headbutting metor and beating all the Tekken Monks, Lidia, Eddy and Yoshimitsu at once. Like Lars he relies more on electric abilities capable of sending thunder from the sky with his punches.
3. Reina
An unknown woman who is in no way inferior to the rest of the Mishima in terms of strength and skills. She has Mishima electric abilities so he is most likely related with them or he just has Mishimas genes she may be also related with Hachijo members because she has Devil Gene powers same as other users. Reina is strong enough to tower in the fight with Jin even though he was weakened but later we can see her being able to face True Devil Kazuya like Lars did altrough she lose she did good so i would assume that Reina and Lars are equal maybe Lars is slightly better because of his experience but... Reina has devil form at the end of Tekken so she's most likely above Lars and i think Heihachi too because of that.
2. Kazuya Mishima
As the next Mishima is the pinnacle of strength and he is the main boss of the last part of the game he fought and defeated people like Heihachi in the past, Devil Jin and Azazel while using his own power but after he possesed Azazel he beats Lars and Reina as well as barely being scratched by combined forces of Alisa, Hwoarang, Lee, Victor and the other two Mishimas (if we assume Reina is Mishima) initially without much paying attention. True Devil Kazuya is strong enough to make his strength cover half of planet when he fought Angel Jin. His powers are the same as the rest of the Devil Gene users except he now has Azazel's powers so he can use his crystal abilities. He will be obviously strongest character if Angel Jin doesn't appear.
1. Jin Kazama

Our main protagonist already from the moment of his debut in Tekken 3 doing impressive things such as beating Ogre who was powerful enough to face Heihachi. He also defeats Kazuya and Heihachi in Tekken 4 as well as Jinpachi in Tekken 5. In Tekken 6 he also beats Azazel but both ended up barely alive after that fight. In Tekken 8, he initially lost his shape and even though according to Claudio his devil is stronger than Kazuya devil he lost the fight to him, later he also lost to Reina and even to someone like Hwoarang or Leroy who, despite being inhumanly strong, are normal people, however he defeated them all (although Reina probably did not take it seriously) after visiting Yakushima he accepted his Devil Gene and mixed it with his Kazama gene, thanks to which he was able to combine the powers of the demon with the puficiation Kazama powers thanks to which he was able to face True Devil Kazuya however it was not enough because of which he unlocked a new even stronger form called Angel Jin which finally helped him defeat True Devil Kazuya. Jin also he can use both Kazama and Mishima styles and all the powers associated with his genes and combined it as he used huge light lasers and also chains that are unique to his devil. Jin in his Angel form was able to cover half of planet with his blows when he fought with True Devil Kazuya. Angel Jin has good counter against True Devil Kazuya because of Kazama powers, is slightly stronger devil and slightly better fighter so he is truly indeed strongest character in Tekken.
Thanks for reading and Sorry for editing it some times.