(CNN) As world powers struggle to fight ISIS, other terror groups are trying to make their mark -- one deadly attack at a time.
Here's a snapshot of some of the most brutal groups, and how they're different from ISIS:
What the name means:
Al-Shabaab means "the Youth" in Arabic. The group also is known by several other names, including the Mujahideen Youth Movement, the Mujahidin Al-Shabaab Movement and the Mujahidin Youth Movement.
What they want:
Al-Shabaab wants to turn Somalia into an Islamist state, complete with a strict form of Sharia, or Islamic law, according to the Council on Foreign Relations. They've even recruited some Americans, including from the Somali-American community in Minnesota.
How big of a threat is Al-Shabaab to the United States?
Who they've recently attacked:
On Tuesday, a truck bomb exploded outside the Somali presidential palace and a popular hotel in Mogadishu. At least 15 people died, and many more were critically wounded.
Less than two weeks before that attack, a pair of suicide car bombings struck a government building in Somalia, killing 23 people, including rescuers.
One bomber rammed his explosives-laden vehicle into the main gate of the building, killing several people. Minutes later, as people gathered to help the wounded, a second car bomb exploded.
While many of Al-Shabaab's attacks are inside Somalia, two of its most gruesome attacks took place in Kenya.
Last year, Al-Shabaab gunmen killed nearly 150 people at Kenya's Garissa University College.
And a four-day long bloodbath at Nairobi's Westgate Mall left at least 67 people dead in 2013. Al-Shabaab said it had sent the gunmen to the upscale mall in retaliation for Kenya's involvement in an African Union battle against them. Kenya has also been a key U.S. partner in battling Islamist terrorism.
How they're different from ISIS:
Al-Shabaab is al Qaeda's proxy in Somalia. So how does al Qaeda differ from ISIS?
ISIS is primarily focused on solidifying an Islamic state over swathes of Iraq and Syria. It might inspire "lone wolves" in the United States and Europe, "but it is not directing its resources to attack in these areas," Daniel L. Byman of the Brookings Institution said.
"Al Qaeda is weaker and less dynamic than the Islamic State, but the former remains more focused on attacking the United States and its Western allies."
What the name means:
In July, al Nusra Front leader Abu Mohammad al-Jolani announced the group was changing its name to Jabhat Fateh Al-Sham, which means "Syria Conquest Front."
The terror group's previous name, al Nusra Front -- or Jabhat al Nusra -- meant "Victory Front" in Arabic.
What they want:
Until recently, al Nusra Front was al Qaeda's branch in Syria. Now, with the name change, Jabhat Fateh Al-Sham has separated from al Qaeda, al-Jolani said.
Like ISIS, the group had been trying to establish an Islamic state, though primarily in Syria. Jabhat Fateh Al-Sham also wants to implement Sharia law.
Who they've recently attacked:
ISIS isn't the only terror group taking advantage of the Syrian civil war. In the past several months, al Nusra Front and other armed groups fired rockets on residential neighborhoods in Aleppo, the Syrian Observatory for Human Rights said.
How they're different from ISIS:
Unlike ISIS, the group formerly known as al Nusra Front has not declared a caliphate. Instead, it has a different technique.
Al-Nusra Front has been building relations with local groups and making itself indispensable in the Syrian opposition "so its power is growing and it becomes inseparable from other elements in the country," said Matthew Henman, head of the Terrorism and Insurgency Center at IHS Jane's, which analyzes international security risks.
So while ISIS "spends a lot of energy fighting other groups," Henman said al-Nusra's method of ingraining itself in the masses will make it harder to fight.
What the name means:
AQIS gets its name from al Qaeda, which means "the Base" or "the Foundation."
What they want:
AQIS is a relatively new branch of al Qaeda in South Asia. The U.S. State Department started calling AQIS a terror group just this summer.
The group has essentially declared war against atheist writers who dare to challenge al Qaeda's strict interpretation of Islam. It also threatens to target judges, lawyers, engineers and doctors "who don't allow others to follow the rulings of the Islamic Shariah."
Who they've recently attacked:
AQIS has claimed responsibility for the murders of secular writers, activists and bloggers in the region, especially in Bangladesh.
Sometimes AQIS terrorists use machetes, like in the hacking death of blogger Nazimuddin Samad.
How they're different from ISIS:
"Unlike ISIS, Al Qaeda has had a long history of engagement in South Asia dating back to the 1980s, when al Qaeda and South Asian militants fought together in Afghanistan," wrote Iftekharul Bashar of the S. Rajaratnam School of International Studies at Singapore's Nanyang Technological University.
"The formal announcement of AQIS' launch in September 2014 by Al Qaeda's leader, Ayman Zawahiri, is believed to be a strategic move to keep its traditional ties relevant in South Asia at a time when ISIS is gaining traction in the region."
Despite their different goals, AQIS and ISIS aren't above trying to outdo one another, terrorism expert Sajjan Gohel said.
"There are instances in Yemen where they compete with each other as to who can kill more."
What the name means:
"Ansarullah Bangla" means "Bengali defenders of God."
What they want:
The Ansarullah Bangla Team is an al Qaeda affiliate based in Bangladesh. Many of their attacks are aimed at silencing liberal and secular voices, especially bloggers. The group has been banned by the Bangladeshi government.
Who they've recently attacked:
The ABT has mostly targeted bloggers and atheists. When American blogger Avijit Roy visited Dhaka last year, he was hacked to death in the Bangladeshi capital. Three suspected ABT members were arrested in connection with his death.
Ansar Bangla has issued a hit list of atheist bloggers, including some targets in Europe and North America.
"Let Bangladesh revoke the citizenship of these enemies of Islam," a statement from the group said. "If not, we will hunt them down in whatever part of God's world we find them and kill them right there."
How they're different from ISIS:
Ansar Bangla is another offshoot of al Qaeda, this one based in Bangladesh.
ISIS actually spawned from al Qaeda, but was expelled from the group in 2014 after spurning the al Qaeda leader's attempts to restrict its activities to Iraq.
Al Qaeda battles ISIS for global jihadist leadership
What the name means:
Boko Haram means "Western education is forbidden," or "Western education is a sin." The group is sometimes called the "Nigerian Taliban."
What they want:
The terror group, an al Qaeda affiliate, wants to implement Sharia law in Nigeria, and uses appalling tactics to do so. Boko Haram recruits child soldiers and uses schoolgirls as suicide bombers.
Who they've recently attacked:
A gang of Boko Haram gunmen raided a Nigerian village in January, killing at least 65 people by setting their homes on fire.
In other attack, two female suicide bombers killed 58 people at a Nigerian refugee camp for villagers fleeing terrorism.
Boko Haram's global infamy soared in 2014 after it kidnapped 276 schoolgirls from Chibok, Nigeria, spawning the international campaign "Bring Back Our Girls."
How they're different from ISIS:
Boko Haram mainly concentrates in Nigera. But the lines between the two terror groups are blurring. Even though Boko Haram is an al Qaeda affiliate, it has pledged allegiance to ISIS.
What the name means:
"Hamas" is an acronym for "Harakat Al-Muqawama Al-Islamia," or "Islamic Resistance Movement" in English. The word "hamas" also means zeal, or enthusiasm, in Arabic.
What they want:
Hamas wants an Islamic fundamentalist Palestinian state. Its manifesto advocates the destruction of Israel, and it calls for the raising of "the banner of Allah over every inch of Palestine." But it also operates schools, hospitals, soup kitchens, orphanages and an effective social welfare program in the territories -- which has helped the group's popularity.
Who they've recently targeted:
In April, a 19-year-old Hamas operative bombed a bus in Jerusalem, wounding 20 people, Israeli police said.
Hamas said the bombing was conducted by a member of its military wing, Izzedine al Qassam, but stopped short of a full claim of responsibility. (The statement came from Hamas in the Bethlehem Governorate, not from the group's official spokespeople in Gaza, where Hamas is based.)
But the statement did refer to the teen bomber as "our son."
In June, Hamas praised -- but did not claim responsibility for -- an attack at a Tel Aviv market that killed four Israelis. Hamas spokesman Housam Badran said the shooting was the "first of many surprises" planned against Israeli forces during the month of Ramadan.
How they're different from ISIS:
Unlike ISIS, which has said it wants to control far more than its strongholds in Iraq and Syria, Hamas is focused on Israel and the Palestinian territories.