Character that makes attacks in as many squares as possible

[Covert Operator]

Aklys (D20PFSRD) lets you make attacks 20ft away [1-handed]
Flying Talon (D20PFSRD) is a Light weapon that has Reach

Wield Armor Spikes, Spiked Gauntlet, or similar; Flying Talon, and Aklys:
@=you, T=threatened A=attackable but not threatened
@TTAA

You could sub Aklys for Whip if you want, but that would reduce it to
@TTA
and make it count as a melee attack, not a ranged one.

[Covert Operator]

Ooooh use a whip and an aklys with Alchemist - Vestigial Arm or Summoner - Synthesist.

Take Relentless Shot for your Aklys. If you've got 2 extra arms, you could wield a random ranged weapon too (obviously you'll have Quick Draw)

[lemeres]

Don't forget lunge, which lets you attack 5' further away with melee weapons on your turn. With that and 5' step, you have 10' more than you expected.

That is 30' with the aklys.

[zza ni]

go alchemist and toss a bomb
...gain levels make it bigger area.(or shape it so you don't hit every thing, your allies would apritiate it.)

don't forget to add enlarge person. large get you X2 reach.

[Treefolk]

Any reach weapon, armor spikes or a Cestus, enlarge person. 20ft radius bubble of threat. If you can squeeze long arm in there, 25ft radius.

[Covert Operator]

It's confusing, but I think that Rope Dart works similar to the Aklys, but no trip and can make iteratives (free action to bring the weapon back to bear, instead of move action).

[Covert Operator]

OK, so Enlarge Person + Long Arm
U=you, R=threatened (natural reach), &=natural and weapon threat, T=threatened (reach weapon), A=attackable (not threatened)

15ft nat reach, 10-25ft weapon reach, 40ft Aklys (provokes)
UURR&TTAAA
UURR&TTAAA

The aklys may not have double reach when enlarged, which means the whip (see below) is better here (worse when not large size)

[Covert Operator]

Switch the Aklys for a Whip, and take Lunge to get a similar area, but not an increased threat area

20ft nat reach, 10-30ft weapon reach, 40ft whip reach
UURR&&TTAA
UURR&&TTAA

[Mythic Evil Lincoln]

Enlarged summoner wielding a lance while riding a gargantuan (enlarged huge) eidolon mount.

That gives you an 11 x 11 square threat range, before adding any funny business.

[Covert Operator]

How does being on a bigger mount increase your threatened/attackable area?
You are still only large size even if your eidolon is gargantuan

[Magda Luckbender]

My Mystic Theurge routinely attacks whatever moves in a 60' diameter circle. That's Large (via swift action), reach weapon, and the longarm spell. That's about 124 threatened squares, and he doesn't bother to threaten adjacent. It's possible to cover a much larger area, of course, if one builds for it. The concept of a Strength-based Mystic Theurge might seem silly, but it sure does work well.

[Mythic Evil Lincoln]

Covert Operator wrote:

How does being on a bigger mount increase your threatened/attackable area?

You are still only large size even if your eidolon is gargantuan

A mounted attacker counts the mount's space as their own for purposes of originating the threatened area.

[Magda Luckbender]

Covert Operator wrote:

How does being on a bigger mount increase your threatened/attackable area?

You are still only large size even if your eidolon is gargantuan

When mounted you may choose to attack from any square your mount occupies. So riding a bigger mount increases your threatened area. The downside is that any foe able to attack your mount can also attack you.

Edit: Doh, Evil Lincoln beat my post by 24 seconds.

[Covert Operator]

Aklys is a ranged attack so it doesn't benefit from effects that increase melee reach.
Here's sample builds (Trips and Disarms):
Fighter 3
1: Combat Reflexes, Lunge
2: EWP Flying Talon
3: EWP Whip
EDIT: Quick Draw will also be pretty important later

Swashbuckler 3 (Swashbuckler's Finesse works with Flying Talon but not Whip or Aklys)
1: EWP Flying Talon
3: Lunge
EDIT: A Human that moves Lunge to level 1, and Two-Weapon Fighting at level 3 would be extremely nice here. Cool build idea

[Covert Operator]

The Mysterious Avenger archetype can use a whip with Swashbuckler Finesse, so take that and use the Swashbuckler build above. Now that would be a fun character to play!

[Scavion]

Man the Aklys is pretty cool.

[FrodoOf9Fingers]

Don't forget to add fluid form O.o

[lemeres]

Covert Operator wrote:

Aklys is a ranged attack so it doesn't benefit from effects that increase melee reach.

Here's sample builds (Trips and Disarms):
Fighter 3
1: Combat Reflexes, Lunge
2: EWP Flying Talon
3: EWP Whip
EDIT: Quick Draw will also be pretty important later

Swashbuckler 3 (Swashbuckler's Finesse works with Flying Talon but not Whip or Aklys)
1: EWP Flying Talon
3: Lunge
EDIT: A Human that moves Lunge to level 1, and Two-Weapon Fighting at level 3 would be extremely nice here. Cool build idea

lunge needs BAB +6. So you can put it off until you got your other basic feats in order.

[Covert Operator]

Fluid form is technically a buff that would add to this, but... it's a very high level spell for you to use it just for this.

[Covert Operator]

about the Lunge prerequisite: oops. You kinda need Quick Draw anyway, if you have the two weapons, so it works out :)

[Lakesidefantasy]

A 7th level Polearm Master with the Pole Fighting feature, Combat Patrol and Lunge feats.

Pole fighting allows him to attack adjacent squares as an immediate action; I believe this allows him to threaten those areas. Combat Patrol extends his threatened area by 5 ft., and Lunge extends his reach by 5 ft.

So now you threaten out to 20 ft., but all you do is threaten because you are using a full-round action to set up a Combat Patrol. However, this increases to 25 ft. at 10th level, 30 ft. at 15th, and 35 ft. at 20th.

6th = UTTTT
10th = UTTTTT
15th = UTTTTTT
20th = UTTTTTTT

Now enlarge him.

Although now that I look at it, maybe Lunge does not work with Combat Patrol.

[SiuoL]

Aberrant bloodrager with two level dip in polearm master fighter use reach weapon, the spell enlarge, long arm and lunge with Mythic Champion's Sweeping Strike.

You can hit every enemies in 30ft every round!

[Covert Operator]

Lunge doesn't work with Combat Patrol unless you are somehow making opportunity attacks during your own turn (which never happens, as Readied and Opportunity actions that your enemies take are both interruptions to your turn, I think).
I want to like Combat Patrol, I really do, but it sucks.

[Cevah]

You want reach? Check out this thread where they get more than 40' reach. The link is to my post, but the whole thread details many ways of increasing reach.

/cevah