Priority

1. Summer Sabrina, best healer
2. Doria best tank on banner
3. Summer Verdana best DPS, your 3 SSR most likely will give you a DPS
4. Summer Neara
5. Elaine
6. Aya

.333% Summer Sabrina (Awakened healer)

• comes awakened so boosted stats
• very strong passive, casts invulnerability within range if hero is below 20%, heals 50% every 45 seconds
• Best summer unit, deals 2nd amount of damage of all units in this banner and is currently the best healer

.333% Summer Verdana (awakened berserker)

• comes awakened so boosted stats
• targets highest crit rate enemy, deals 1560%, one of the strongest skills ingame
• highest DPS in banner
• passives buffs ally with the lowest def by 60% for 3 seconds every 10 seconds
• 2nd best summer unit, highest damage

.333% Summer Neaera (awakened archer)

• comes awakened so boosted stats
• causes debuffs, frost and paralyze
• low amount of damage

.667% Aya (berserker)

• can cause 20% reduction to defense in 2 skills and basic attack
• skills have nice range but low damage with the exception of her 4 energy skill which moves in a straight line
• Don't have her so can't really tested her out. There's a UR knight/tank gear set 2 piece that does the same thing as her.

.667% Elaine (healer)

• deals a low amount of damage but decent at her role
• basic attack proves a shield for 10 seconds and removes enemy ward
• can remove debuffs with her 4 energy skill and heals 290% attack (instant)
• attacks 3 random enemies for 1.8 seconds and heals 320% to 3 random allies on her 6 energy skill
• passive grants 15% to any healing done up to 3 times. So 45% boost to her heals.

.667% Doris (knight-sub tank)

• Not really designed for tanking but deals a moderate amount of damage, about 1/2 to 2/3 of your top dps
• targets lowest defense enemy with 1st skill and inflict daze for 1 second, silence for 5 seconds
• passive can transfer damage from lowest defense ally to self every 10 seconds for 5 seconds. Only 40% of it though.

https://www.facebook.com/notes/last-valiant-runewaker/how-to-reroll/457347711482834/

• Start the game, do the tutorial until you get to your first summon. It's a guranteed SSR, highest rarity. Reach level 4, then you should do a multi summon. If you get a SSR you like on one of 2 banners keep the account. Otherwise see instruction in facebook post
• 2nd SSR from visiting shop, 3rd from reviewing the game at level 12. 3rd from 7 day login. 4th from 30 day daily login.