Star Force grants the following abilities:
-When selecting cards from the custom screen, normally you are only limited to cards that are in the same column or identical cards. (White cards are an exception as they can always be selected no matter what). While using Star Force, you may also select across a row (though you cannot do both rows and columns at the same time. Only one or the other).
-Your charged shot will change to an elemental attack.
-Countering will normally add an extra copy of a random card from your Card Force folder to you selection for that turn. While using Star Force, countering will instead add a giga-class card to the end of your selection known as a Star Force Big-Bang. These attacks are unique to their specific Star Force and up to three can be used in a single turn if you are able to accumulate that number.

Your new charged shot. Ice Pegasus will fire a quick shard of ice down the column. It it hits an enemy without status guard, that enemy will freeze on the spot. However, unlike other freezing attacks, it is very easy to break out of the ice from an Ice Slash and will only take a second.

Your Star Force Big-Bang. Ice Pegasus will leap into the air when this attack is used and time will freeze. A magic seal will appear over the last three rows of the enemy area before the 3x3 area is encased in ice, dealing damage and freezing all in place for several seconds.

Your new charged shot. Fire Leo will unleash a stream of flame down the column. This attack is powerful but will grant the enemy a few seconds of invincibility like many card attacks do.

Your Star Force Big-Bang. Fire Leo will break into a stance and build up power when this attack is used and time will freeze. A 3x4 area in front of Fire Leo will glow before Fire Leo unleashes a giant scathing laser attack ahead of him. If used from the center panel, this attack will cover the entire enemy field.

Your new charged shot. Green Dragon will fire three volleys of leaves down the column he stands on as well as any adjecent columns (so if he's in the center, he'll hit all three columns). Leaves fired down the same column will travel all the way down the enemy area while leaves fired down adjacent columns will only travel three panels before fading.

Your Star Force Big-Bang. Green Dragon will begin to swirl in place when this attack is used and time will freeze. Green Dragon will turn himself into a 3x3-area-engulfing cyclone and rush forward. Everytime the cyclone moves while in contact with an enemy, damage is dealt. (In other words, all enemies in the path of destruction will be hit three times). If used from the center column, this attack will essentially sweep the entire field. This attack will also instantly bypass barriers and auras as if they weren't there as well as eliminate them automatically.

-All of your brother's records will be added to your game. This will help reveal what cards are a part of the library as well as grant benefits from SP boss deletion times.
-Members of your Brother Band will grant you their Brother Force, a special white battle card that will either become a copy of one of their six "Favorite" cards (besides making up the Brother Force you grant to others, Favorites will also automatically become white cards in one's deck.) or their Best Combo Legend Force if you are playing with your friend nearby via Wireless play or in a VS Wave Battle.
-Members of your brother band will grant you a special "Link Ability", which differs depending on the version.
-Through Wireless play, if you are nearby a friend who is also on your Brother Band, as long as your friend is within range of your connection, he will show up on your Brother Band as "On Air". If the two of you have any of the same battle cards in each of your folders, both of you will receive a Share Star on that card. It is possible to have a maximum of six share stars on a battle card if seven people play together within range of each other.
-If a member of your Brother Band is playing a different version than you, you will gain that person's Star Force transformation.

In addition to human Brothers, the game allows you access to five other in-game brothers (though they will never go beyond Level 60. The link abilities are as follows:

To create a best combo, after you receive Star Force for the first time, challenge an EX or SP level boss and perform 300 damage or more to them in a single turn. At the end of battle, you AM Satellite will contact you. He will then walk you through the set-up of the combo. The strongest setup you used in a single turn will be the setup that will become your Best Combo. If you dealt the exact amount of damage in a turn twice in a battle, and both satisfy the condition of a Best Combo, the latest setup will be used. You can give your combo a name as well as configure what your character will say as he initiates the combo. After creating a combo, you may visit Legend Master Shin at the rooftop of Amaken and purchase a Legend Force card for 3000Z. You may own up to 10 Legend Force cards at a time and only one may go into your folder at once. Once it's used, it's gone and you must buy another.

The Legend Force will be named after your equipped combo and using it in battle will cause time to freeze as your character will activate the Star Force of your version, autotarget an enemy (or enemies depending on the combo) and unleash the entire fury of the combo. When a Legend Force card is selected in the custom screen, no other cards may be included in the selection. Another way to use a Best Combo is to have it appear via Brother Force when that particular brother is On Air via Wireless play.