Luogu Puzzle Hunt 1/光暗之元

光暗之元 (The Meta about Light and Darkness,link) is a middle puzzle in LGPH 1.

Content of the Puzzle

[20] -> [8] [6] [6]
-----------------------
從中斬而為貳
-------------
pop -> o
radio -> d
misdeed -> d
[8] -> (8)
-------------
summer -> m
conflict -> i  
ascent -> d
[6] -> (6)
-------------
stasis -> s
byebye -> y
mirzam -> m
[6] -> (6)
-----------------------
(8 6 6) -> (6)

Solution of the Puzzle

This is a meta puzzle. The number "20" means the answers to all the 20 small puzzles.

Before figuring out how to divide 20 small puzzles into three groups, take a look at the examples of these three groups:

The first group of puzzles: The prompt is "odd", and it can be found that it extracts the center letter of odd length words.

The second group of puzzles: The prompt is "mid", and it can be found that it is the average value of extracting the middle two letters of even length words.

The third group of puzzles: The prompt is "sym", and it can be found that it extracts the only pair of letters with the same symmetrical position from even length words.

To be assigned to the third group, the restrictions on the answers to the small puzzles are greater than those in the second group. Therefore, for a small puzzle with an even length of answer, if it can be assigned to the third group, it should be assigned to the third group; otherwise, it should be assigned to the second group.

So, we can devide the 20 small puzzles into three groups like this:

01 believe    -> i
03 illness    -> n
06 endoflife  -> f
07 white      -> i
08 givenname  -> n
13 tsing      -> i
16 sixteen    -> t
20 license    -> e
------------------
02 electronic -> s
05 assume     -> t
10 egyptian   -> r
14 symmetry   -> i
17 handheld   -> f
18 hair       -> e
------------------
04 ironwood   -> o
09 noprogress -> r
11 existing   -> i
12 rightangle -> g
15 liquid     -> i
19 functional -> n

Search for "Infinite Strife", and you will find that the music game Arcaea has a track called "Infinite Strife,", so the answer is "arcaea".

In fact, all the example words have appeared in the track names included in Arcaea (byebye did not appear, but bye did), which is intentional. The "light and darkness" in the title points very vaguely to the plot of Arcaea.

(And then some contestants guessed out the answer with this, that's really unexpected)