The Immortal Composer, Siegfried, of course. Followed by Renka.
Takeda is probably my favorite because unlike Kenichi he lives to fight and doesn't fight to live. Siegfried is an very interesting character too and he's funny, so he'll be my second favorite
Siegfried and Hermit are probably my top two fighters. As a character, Nijima takes the prize for me. What would Shinpaku Alliance be without their Alien Overlord?
I'd like to say Seigfried because he's obviously the strongest at this point without counting Renka or Hermit. Plus like the masters say, he's a genius
And then my second favorite would be Kisara because of her talent and he Raw animal instincts .
I can't actually say I like members of Shinpaku Alliance that much, but if I have to choose among them I would go with Nijima.
Even though he is annoying at some points, he still gets the funniest moments mostly to this manga. Especially I like his interactions with Kenichi and his "minions".
The Valkirye Kisara Nanjou, followed by Ikki Takeda.
Niijima as mentioned there wouldn't be an Alliance without his plotting, ever since Beserker chase he's just too funny and persistent. 2nd would be Seigfried he's grown on me a lot and is actually the most talented amongst the group able to train himself he has master potential written all of him...Takeda is easy to like but his character has been shunted a little if you ask me he's not developing at a impressive pace even with a master...Freya is my 3rd choice she's Hot only black chick in the manga and does her thing during her battles, just wished she ha more exposure fighting cause she rocks with his staff technique's.
For me natsu, seigfried and takeda tied for the first place. Seigfried is just plain hilarious and natsu and takeda are characters that actually make sense. Takeda and natsu are reasonably talented individuals who work their asses of to become respectable martial artists. They have the decency of not being unable to fail thanks to their "falling" to mastery. Overall they would be the more interesting members of the alliance. Freya, kisara, thor and ukita overall seem less commited to their martial arts and seem to have far too little relevance to the plot to be interesting. Nijima is cool too even if he isn't a martial artist. I guess he gets points in the manga for being the only one there to actually have real life skills.