Scrap the logs.

Scrap the Logs, add A level System.

It should be like a Goa level system but different, such as, you get 100 Points at charater creation. You can spend the points on Taijutsu Specialty, Ninjutsu Specialty, And Genjutsu Specialty. Depending how how you spend, thats how much Nin / Gen/ Tai you gain per level.

You could gain exp several ways.

1) Usage of Jutsu
-- The exp of a jutsu could be preset to wear you gain each time you use the jutsu. To prevent afking, A jutsu should have a Cooldown. Like, a 20 second cooldown on goukakyuu, or a 10 second on a housenka. Another way would be to stop gaining exp for jutsus if you spam it. Like, if you use gouk 10 times in a row, you wouldnt gain exp, but still gain uses.

2)Killing other people
--Simple. Kill another person, gain 10x the exp as there lvl.
ex.
lvl 1 = 10 exp, lvl 10 = 100 exp, lvl 100 = 1000 exp


3) Sparring

-- Sparring could be as simple as clicking a verb, or getting teleported to and arena to fight to the death, depending on how you code it.

I hope you chose the last one.The last one could give half the exp if you win,and a quater if you loose, comparing to if you really faught, but the upside is, you dont gain deaths.So...
ex.

Sparring a lvl 1 = 5 exp on win , 2.5 exp on loose.

lvl 10 = 50 exp on win, 25 on loose

lvl 100 = 500 exp win, 250 on loose