if you read back, Haseo is explaining the quests and theres a bug here and there.
I believe Haseo has added quests to explain the mechanics, he added a bunch of tutorials here and there so that you know what to do, but, if you missed that, its easy to do it wrongly.
for the story mode, you will be playing a character that is reanimated into the world and controlled by death. the Mc will have access to darkness energy (the knights channel), but you need to apply points to use it, with the cost of STR.
its not recommended to add points from start, only when you get your first "darkness" weapon, that is a "cane", and later "cannon". when you get that you need to be able to equip it. a cane require STR and INT.
do not add DEX or LUK at all. those stats are used by other jobs, that you will not be able to join since this is a "story mode".
in free-mode there will be 5 jobs to take and they will require different ability points.
the ability build for this "darkness build" is to have STR equal to your level. so if level 10 you have 10 STR.
when adding skills points to the knights channel it will cost 1 STR each level, that means u need to increase STR as well, adding enough STR to reach your level. everything else should go to "INT".
for cane, it will do both weapon damage and darkness damage.
the weapon attack is based on the weapon attack point and STR, while the darkness attack will be based on INT but also darkness energy that you get from "the knights channel".
you will feel its weak initially, until you get more points into INT and more skill points into the knights channel.
if you do it right, when you get your darkness attack skills, you will notice a huge increase of damage.
for cannon, its different, the cannon itself is useless. theres no ammo and "people in mapleworld" dont use it, but it can still be found from monster drops, like a relic. but, in our build, the cannon can be used to focus the darkness energy to make a huge attack. that is why, the cannon itself without a skill it useless. but with a skill (Knights Blast) you do tremendous damage, and it has a small range as well, damaging everything within the blast. this skill is one of the strongest in the first tier for all jobs.
cannon is a 2h weapon, so no shield is allowed, but cannons gives u a bit of defense, the only weakness is that is slow, but its also ranged, that means it gives u a bit of time to kill the monsters off before the monster attacks u.
when u play, its important that you check the bestiary. its not recommended to attack monsters that are higher than u in level.
Haseo can help u if u did it wrong, talk to him, give him your ui_char.dat if you want to "fix" your character.
I can also help, if you want to re-arrange your "ability" points, if u mess up. send me your ui_char.dat
later in the game, there will be a way to "reset" your ability points, there will be a shop selling that.