Overview
Pros
- Currently the best costume for reducing enemy damage.
- Sage makes Olstein's existing kit better.
- Disrupting enemy attacks is a consistent theme with his base skill.
- Very low SP cost (1 SP).
- Olstein has great defensive stats and is fairly tanky.
Cons
- Very low skill damage.
- Damage reduction is a very niche role, and there is not a lot of content right now where it is needed.
- Removes stat enhancements, but does not remove other types of buffs (e.g. Energy Guard).
- ATK/M.ATK reduction only lasts for 2 turns (i.e. 1 enemy turn). Since the cooldown is 5 turns, you cannot keep it up on all turns.
Olstein for PVE
Olstein's niche in PVE is reducing the impact of strong opponent attacks and skills. There are other units that can achieve a similar effect, but Olstein is the best to date.
When it comes to ATK/M.ATK reduction, the obvious comparison is with Celia. Celia's Curse costume reduces ATK by 65% at +5. Celia's Descendant costume reduces M.ATK by 65% at +5. This comes pretty close to Olstein's 70% reduction at +5. The reduction on both of Celia's costumes also last for 4 turns, which is better than Olstein's 2 turns. In most cases, if you just need damage reduction, you may find that Celia is a very decent substitute to Olstein.
However Olstein has four advantages over Celia in specific kinds of battles.
Firstly, Olstein is cheap. At +5, Sage Olstein only costs 2/1 SP. On the other hand, Celia is expensive: her skills cost 5/4 SP. Note also that Olstein's Fiend Scholar ability can recharge your team's SP. This SP cost difference can become significant in longer battles, as it means your team can afford to use more skills more often.
Secondly, Olstein can reduce both ATK and M.ATK at the same time. This advantage is niche because there are not a lot of levels where you face strong physical and magical units at the same time (though of course, there may be more of them in the future).
Thirdly, Olstein has access to silence (skill block) and SP drain with his base costume, Fiend Scholar. This adds further versatility to his kit when facing dangerous enemies. Note however that many PVE bosses are immune to silence.
Fourthly, Celia does not have stat buff removal. Olstein's stat buff removal works well against bosses that "charge up" their attack power, such as the upcoming water fiend boss. Another example is in Story Chapter 9, where most battles involve attack boosting enemies.
In summary, the biggest benefit to Olstein is that he is an all-in-one package. If you need to increase the endurance of your team, you can use Celia/Red Hat Rou/Top Idol Helena, if you need silence you can use Lucrezia, and if you need buff removal you can use Schera/Eleaneer. But if you need to use all 3 in the same battle, then Olstein is the only way to go.
Olstein for PVP
Sage Olstein is primarily a PVE unit, and not the best suited for PVP.
Sage Olstein can perform reasonably well in PVP because his skill only costs 1 SP at max level. Although the skill does negligible damage, for a measly 1 SP, at +5 costume level you may be able to addle multiple opponent attackers with his 70% damage reduction, and improve your team's survivability to your next round. Olstein also has reasonably tanky stats with his exclusive gear (3003 base HP with +54% HP exclusive gear stat), making him a decent frontline unit.
In addition, Olstein's Fiend Scholar skill can win games in PVP if it hits the opponent's key attackers. Fiend Scholar silences your opponent for 4 turns (2 opponent turns) and also drains SP, which can give you the space you need to close out the battle. The two Olstein costumes work well together.
Having said this, Sage Olstein is unlikely to see much play in PVP because he would really need to be at max level costume to reach 70% ATK/M.ATK reduction, which is a huge investment. He is also unlikely to be reliable or consistent enough to be worth the investment: E.g. Olstein could hit a tank and waste his skill, or an enemy Lathel Homunculus could boost the enemy team back to levels where they can do legal damage again. In most cases, for 1 SP, a Lathel Homunculus or knockback skill would achieve more consistent results.
Olstein for the Water Fiend
It's no coincidence that Olstein is being released ahead of the upcoming water fiend boss. This new fiend boss has abilities that buff its ATK every turn. Having Sage Olstein will significantly improve your survivability, especially at higher levels.
In particular, note that you need to use Olstein on Turn 4 (before other attacks) in order to remove the ATK buff and receive the 300% damage amplification bonus. 300% damage amplification is huge and can't be missed. If you don't have Olstein, then your only other choices will be to bring Schera or Eleaneer to remove the ATK buff. However, Schera and Eleaneer are inferior in higher levels because they cannot reduce ATK to improve your survivability on Turns 2 and 3.
See the slideshow below for a quick turn guide for the fiend boss.
Conclusion
Having at least 1 copy of Sage Olstein will be very important for players wanting to challenge the higher ranks of the water fiend boss. I would recommend pulling 1 copy for that purpose alone.
Sage Olstein can also make late-game PVE battles easier to survive, but his uses are relatively niche. Celia can be a decent substitute where damage reduction is required. We don't have enough late-game content yet to know how useful he will be, but if you already have a strong main team of attackers, pulling Olstein may be a good way of future proofing your team against harder content in the future.
