The only arcane casters are known to come from a certain family line. This family was one of the families that helped build the divine coalition, and as such all of the people who are descended from this line descend from the high elves of the south. There are a few high elves that still practice this magic, even fewer half elves, and most notably there are scarce humans with distant elven blood who are able to cast arcane spells. 

There is no blood restriction on those who can tap into the arcane weave technically. With enough practice and study any wizard can cast an arcane spell, but the difference is that someone with the bloodline may spend a month learning a new spell that other wizards would take years to even understand. 

Training in the Arcane

When you adopt this tradition you gain gain proficiency in the arcana skill if you don't already have it. 

You also gain the ability to cast arcane blast at will.

All spells that deal force damage now deal arcane damage.

Mark of the Arcane

When you successfully cast arcane blast on a target, you may choose targets within 5 feet of that target and all targets within 5 feet of those targets, up to three jumps. Those people within 5 feet are marked by you and the next targeted spell against them effects all of them as long as they stay within 15 feet of each other. 

Once a target moves out of 15 feet from another mark, it breaks the mark on only that target. 

Mana Pool

You gain a pool of charges equal your spell casting modifier which recharge every long rest or you can gain one by taking a short rest while you meditate within a marsh, plains, or island environment.

You gain the following powers that can be used as a bonus action:

1) When you successfully damage another creature with arcane damage, you may expend one charge per creature and force the creatures to make an intelligence saving throw. Upon a failed save they forget 1d10+ your spellcasting modifier level spells. Ie: you roll a 5 and add 2 for your intelligence and proficiency. They would lose all of their level 7(or next highest level spells from their memory). This effect does not work on creatures who do not have spell casting. 

2) you can expend a charge to raise the save DC of your spells by 1, you can do this before or after you know the results of their save.

3) you can expend x charges to recover a spell of equal level to charges used.

Overcharge

At 14th level you can cast all of the simple spells you know at maximum proficiency. When casting an arcane spell of 5th or lower, you always deal maximum damage. This power can be used once per long rest for free. You can also expend a charge or take 2d12 arcane damage to use it again. Each time you take damage from this feature increase the damage by 1d12.

At level 20, you can use this power for free. Your arcane spells always deal maximum damage when cast at 5th level or lower