But there is something else to this: In Hard Mode and later, Olga Flow will do its body-switching technique, turning you into Heathcliff Flowen. If you've fought Olga Flow's second form before, you'd notice he had a ??? Attribute. This means that this form will take on a random attribute from the game, whether it be Native, A. Beast, Machine, and yes, even Dark. Hunters and Rangers must keep weapons that have percents to any of those attributes (again, save those guns!) so that they can be used on the body-switch. This is important because Flow will inherit one of those attributes randomly, and only one will hurt it. Forces will deal with this a different way, as it'll be explained later.

ALL DIFFICULTIES
First Phase
Defensive Strategy:
Olga Flow is flying around the descending platform you're on, and it'll do a multitude of attacks. It'll execute four attacks followed by two variations of different attacks that are executed randomly.

Attack One: Sword Beam
Simple. Just stay away from being directly in front of Olga Flow. It'll do this a couple more times. This attack extends to a straight line across the platform.

Attack Two: Mass Slash
A bit tricky. It requires you to stay at a distance in front of Olga, but you don't have to stray too far from its sides.

Attack Three: Diffusion Bullet
Now this one's a bit hard. In Normal and Hard, it seems that you have to be right in front of Olga when the green pulses come at you. And in Very Hard and Ultimate, you'll probably have to be away from Olga and run to a side when they come at you. Beware: the pulses can home into you.

Attack Four: Charge Laser
Ouch! When you see this one, you'll need to run with the way it is rotating, and staying close to its center.

ALL DIFFICULTIES
Defensive Strategy:
Olga Flow got two new cronies to assist him: Gael and Giel. If they're close to you, they can pretty much mess you up, so take them down from a distance. These enemies fuel Olga Flow's more powerful attacks, which can sometimes take down a hardy Hunter. Gael and Giel will inherit the current elemental weakness to Olga if you're using techniques. Olga Flow can also somehow bring on raining debris which is pretty random to avoid the debris itself.

Olga Flow loves to walk around. It also loves to use very powerful beam attacks to almost kill you instantly. When Flow is pointing its sword into the air, you better run away and you better pray you can survive (bring Scape Dolls!).

Lastly, it's a good idea to cast Jellen and Zalure on Flow. Zalure is obvious while Jellen will only affect its stomps, not its energy attacks.

Offensive Strategy:
Hunters/Rangers: There really is no strategy other than hack-and-heal. Just stay at a distance with your gun and shoot away. Watch out when the mines appear because touching them can hurt you. Olga might get close, so keep a lookout (if you can, really) if it looks like Olga's going to attack with its energy-based attacks (you know, the flashy things that really hurt).
When the body transfer is in place, and if the current weapon isn't dealing any damage, switch to another gun and see if it works. If it does, attack as you would do.

Forces: Olga Flow will purposely reduce your TP. It'll be randomly weak to one element, INCLUDING Grants. Yes, even in Normal Mode, you're going to have to bring Grants with you.

Simply fire a Foie/Barta/Zonde/Grants blast and see which one does the most damage, and stick to it. There really is no way when to tell to switch elements. When Olga does his body-switch, you have to fire off everything you got again to see what damages Olga Flow, not yourself because the wrong element will hurt you instead (don't worry; Olga has an elemental defense to the incorrect spell you might use so you don't kill yourself on accident).