I recommend you read Battle Sprite Skill Details and Battle Sprite Ultimate Skill Details carefully.

Drakon seems intended for frontline fighters (that's you if you use mostly swords). The fireball can make up for the lack of a ranged weapon against switches, and as an opener before you run into battle. It also packs a decent amount of interruption and knockback. The flame barrier will protect you and provide additional damage if you're up-close, which works particularly well with cutters. Firestorm just sets a bunch of things in an area on fire (until you get the ultimates) and will help you soften up targets so you can kill them faster.

Drakon's abilities will not be more powerful than your own, they will just be different. Keep this in mind. If you wanted a companion with abilities called "More DPS 1", "More DPS 2" and "More DPS 3", you may find Drakon disappointing. If instead, you want abilities that sound more like "interruption", "protection" and "area damage", you might find what you seek in Drakon.

Seraphinx seems intended for guardians. The laser is not too impressive, damage-wise, but can be used to push back enemies and create a wall which gathers up and holds back enemies. It works really well with heavy swords and can help you set up a cluster for troika charges. Heart attack marks enemies and gives them a chance to drop hearts in addition to whatever else they were dropping. That's a close to healing as you're going to get in this game. The angelic aura is kiiinda weak and lasts for like 5 seconds. However, as long as that barrier is up, you won't be interrupted from whatever you're doing. This is great if you're using a slow weapon you need to charge up or spam to get out of a sticky situation. One of the ultimates for the angelic aura lets you get up to max CTR even if you're only at medium with the weapon, and it basically seems made for someone in plate armour to launch a risk-free troika-charge.

Seraphinx is not intended to make the game easier for you. Instead, it will support you and your party if you are skilled at using the abilities. The laser beam has a hit limit of 5 hits that's been officially confirmed as intended, so if you wanted a sprite with a highly damaging primary attack, Seraphinx is not it. The abilities should not be read as "do damage", "party heal" and "invincibility". Instead, think of them as "barrier", "damage control" and "backup shield".

Maskeraith is is a supportive sprite. It has the potential for massive damage, but only if used correctly. Caustic Quills add about 200 damage per hit to weapons for 11 or 22 hits (depending on ultimate picked), but only if you use a fast weapon like cutters or spread the damage over a random assortment of enemies.. It's also nice for spreading poison when there are healers about. The cloak turns you invisible, but you can't charge your weapon while cloaked or anything. If you'd rather the cloak description read "this skill gives you a free charge attack", then I'm afraid you won't enjoy the ability much. The third skill is a mobile haze bomb that plants sticky bombs on enemies in range. It can deal a total of 750 damage to a crowd over the 10 seconds its active, during which you are free to supply your own damage.

Maskeraith will not fight your battles for you, but he can widen your options and empower your attacks if actively work to implement his abilities into your playstyle. The abilities are not to be interpreted as "kill that enemy for me", "free x128 damage backstab button" and "kill everything for me". Instead, view them more as "boost my combo", "tactical reposition" and "finish off this crowd with me".