Returning to Heroes!

Ok, here should be the main points.

Non-gameplay wise
Manuals: you can now transform your heroes into manuals. They take a space that is different from the barracks and you can have 999 of them (basically expanding barracksà. However, these manuals remember only your heroes rarity and skills; not their IVs. You basically want to manual every hero whom you want to keep as fodder but don't want to build. Since manuals have no level, you can also unlock the potential of a manual directly.

Accessories: heroes can now wear cool accessories. They are almost exclusively "hats" for now. They always have been available only for a small amount of time and there have been no reruns.

Gameplay wise
New mode: Forging Bonds. You play a simple map to earn points of "friendship" with the focus characters of the events. You can obtain orbs, feathers, badges and accessories.

Relay Defense. You defend forts against enemies with inflated stats that spawn endlessly. Controversial at first, IS fixed the mode now. It's basically reversed Rival Domains. The rewards are orbs, feathers, crests, badges.

Abyssal difficulty appeared. It's a crazy difficulty for LHB and GHB that reward you with a golden version of an existing accessory.

New Arena system: you now receive bonus points when killing with a bonus unit, which completely changed the gameplay from having three good units do the run and a useless bonus units to three cheerleaders doing their maximum to make the bonus unit so everything.
There is also a new tier in Arena, indicated by a little crown and a number representing the number of weeks for which you have been in this tier 21.

Other
New levels of BST. The highest BST is now 180. The two units concerned are Legendary Young Tiki and Halloween Myrrh.

New A-slot skills: Duel. They allow certain type of units (Green Infantry, Colorless Infantry and Red Flying for now) to have 170 BST in Arena, making them more usable at high levels. We expect to see this skill for every type of unit, except maybe Armors.

There are other things such as new seals, new refines and new notable skills such as Special Fighter, but this is becoming very specific.

Finally, and this is a personal advice. If you rerolled only yesterday, you should reroll again now, gather orbs and wait for the legendary banner in december. Not only will Book 3 be out and probably new game mechanics as well, but this is where you'll make the best use of your orbs as well. If you can't wait this much, you should at least wait for the legendary banner on october 31st.

Oh yes, and from the free pull on the CYL2 banner, do not pick Celica, she's not that good. Pick Veronica, she is by far the best unit from the banner.

all you have missed is a couple thousand orbs. IS hasn't done much lately but we will more than likely get a feh channel soon.

Xhamos covered a lot of important points, especially the combat manuals.

Plot: play to the end of Book II. There are some touching moments near the end along with the usual rawr kill Surtr

HM farming: GHBs (including the daily rotations that repeat every week) are 0 stamina, and even rival domains and relay defense is 0 stamina, so people have been devising strategies to autobattle these modes, sometimes at the level 35 difficulty, for HM on various units to get more feathers.

Arena:
- this is a change that overturns foundations. IS decided that you get 3 bonus points whenever your bonus unit gets a kill, so now all competitive players try to kill everything with bonus units. I personally think it just makes the arena even more bogus than it was before.
- score inflation via BST: CYL2 armours both had 174 BST with superboons available, and the same is true of L.Hector who came before them. L.Tiki and H.Myrrh have 180 and 179 BST respectively, and H.Myrrh has two superboons available. L.Hector and L.Tiki increase the score of heroes with the appropriate blessing.
- score powercreep via SP: CYL Hector has a 350SP A-skill. Quan has rally spd/def+ which scores 400SP, which is equal with prf assists such as Micaiah's sacrifice. Ophelia has rally up atk+, which is actually a very interesting skill (on triple tactics Titania, for example - see her weapon refine) and also scores 400SP. Healers have 300SP balms (but they still lag behind when other units are using 500SP specials) inheritable from B.Veronica and Loki.
- score inflation via SP: CYL Celica introduced the first 300SP A-skill that isn't DC or CC, namely, death blow 4. Brave Redux (which is basically Farfetched Heroes 2) introduces fortress def/res, which is also 300SP, and all duel skills are 300SP. Duel skills are a new series of A-skill which is basically IS saying "ok, well you guys were already putting DC on units that made no sense with it, so here, have 5HP to go with it and now your unit scores like +spd Sheena or Gwendolyn" (or if the unit has a prf, actually higher than Sheena or Gwendolyn, so PA Azura is now actually capable of outscoring Sheena, as are Caeda and Soren). Owain has introduced the first 500SP special with burst damage in blue flame. None of these skills really do much to the score ceiling for f2p players (except maybe duel skills because Sheena and Gwendolyn don't have prfs), but they do mean that competitive players have more options.

Other points about new skills and PvP meta:
- starting from CYL2, armours tend to force doubles against you on both phases. Both CYL2 armours can do it with their base kit, as can H.Myrrh.
- special fighter. Guard down to 50% and a free extra special charge for you on both phases. Comes on CYL Ephraim and he's an absolute monster with forced doubles on both phases independent of HP.
- witchy wand: inflicts guard against opponent units and resets their special cooldown. So now there's a counter to infantry pulse.
- special spiral and Dark Mystletainn: the prf came first, and then its effect got released as a B-skill with massive implications for a lot of infantry, especially stuff like OHKO mages.
- might already have been here when you left: restore+ is a very good healing skill.
- link skills: available on Laevatein, B.Sanaki, Sumia, Nina, and possibly others not coming to mind. Also on Odin's prf refine (yes, he got one, and it's very interesting.)
- skills such as steady posture
- darting stance and brazen atk/res recently got released as seals
- infantry rush and flash. Basically a drive, except it grants heavy or flashing blade. Good options for infantry teams.
- Distant and close guard: C-skills. I'll leave you to do your homework. They work on both phases.
- Same with wave skills.
- Increased fodder availability: for example, atk tactic is available at 4* now via Legault.
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- coloured daggers and bows: currently, L.Lyn and L.Lucina are the only two coloured bows. Hoshidan festival dancers, Flora, and H.Kagero are the coloured daggers. H.Kagero is currently the only armoured dagger. Breakers do not work against them because breakers specify "colourless dagger" or "colourless bow"
- we have two more flying dancers/singers, B.Ninian and YT Olivia. Also there are the Hoshidan festival dancers, who are rather combat-capable and have very interesting weapons you'll want to know about. (Also, they're coloured daggers)
- Silvia is a relatively new dancer available at 4*.
- The definition of "fast" has gone up a few points of spd. See https://fireemblem.gamepress.gg/q-a/karlas-generation-analyzing-spd-powercreep
- Units you need to know about: B.Veronica, B.Hector, B.Ephraim, L.Hector, L.Marth, L.Tiki, L.Lucina (not so much for arena as for Future Vision), H.Myrrh, Karla, Ophelia, Flora, HS Micaiah, Owain, Titania (weapon refine), Celica (weapon refine), both infantry Tikis (prf with effect refine), summer young Tiki, WF Hinoka, M.Corrin (weapon refine), Camilla (weapon refine), Clair (if you don't know about Rhomphaia, it's basically Wing Sword but a lance), Ishtar (hits insanely fast and hard without a blade tome), SF Nino (similar), probably others I missed.

Some analytical points:
- L.Tiki more or less eclipses Nowi completely. See https://fireemblem.gamepress.gg/q-a/there-still-any-reason-merge-nowi
- Due to bonus kills in arena and duel skills, infantry dragons probably lose their place in the meta. They lack prfs so they will get outscored, and they're not prime support units.
- Healers and dancers still can't compete with other units in scoring despite duel skills due to their assists only being 300SP and their highest-scoring specials being also 300SP and all but two of them lacking prf weapons
- Arena is a dubious mode, as I alluded to earlier. See Updated Thoughts on New Arena pt1: what's wrong with arena
- The entire game is descending into absurdity and stupidity. Abyssal mode, arena bonus kills...

Also, i don't think Xhamos mentioned tactics drills. "Puzzles" would be more accurate, but it's a good mode. Not without its issues, but a good mode.

I might have missed some things, but that should help.