Ansarallah, more often called the Houthis, are a Yemeni political movement, who together with the Almotamar Party, form the independent government of Yemen, that rules over 80% of the population. The Saudi-UAE backed government meanwhile, is based in a hotel in Riyadh & controls empty desert and some border crossings to prevent journalists from filming Yemen. (https://www.youtube.com/watch?v=j_aOfoO118M)
Many news media sources refer to them as the "Houthi Rebels" which may have been true around 2004-2011, however their holding of the majority of the country, & the resignation of Hadi with the help of many in the Yemeni Army, proves that they have clear continuity with the past governments of Yemen
Foundation
The Ansarallah, gets the moniker Houthi because they were founded by the Prominent Zayidi Cleric Badrideen al Houthi, & the leaders have been his two children, first Hussein, then Abdulmalik after Hussein was killed. During the peroid from 2002 to 2011, there was intermittent fighting between the Houthis & the Yemeni government, but every since the resignation of al-Hadi in 2015, the Yemeni government & the Houthis have been cooperative, excepting a few incidents. al-Hadi ran back to Aden & called the Saudis to help him, which lead to one of the worst humanitarian crisises of this century, with the Saudis blockading ALL ships into Yemen, & causing the deaths of nearly 50000 children (https://www.chicagotribune.com/nation-world/ct-save-the-children-yemen-20171116-story.html).
Blockade of Israel
In response to the genocidal actions of the Israeli government towards the people of Gaza, the Yemeni navy has seized many cargo ships headed towards Israel. These blockades are a legitimate as an act of war according to International Law, because the Ansarallah are claiming to be the legitimate Yemeni government & they have declared war against Israel another recognized state, unlike the previously mentioned Saudi blockade, because they claim to be interfering in a civil war, where Humanitarian Aid MUST be sent. The US sending the Navy to stop this blockade means that America has officially joined the War against Gaza & Yemen on the side of Israel and Saudi Arabia, two states that have no problem with the mass murder of children.
Houthi Media